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Latin 8 - 6-B Vocabulary
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Owls, such as the young snowy owls on the previous page, have for centuries been symbols of both wisdom and mystery. To many cultures their piercing eyes have conveyed a look of intelligence. Their silent flight through darkened landscapes in search of prey has projected an air of power or wonder. For this chapter and this book, owls are an engaging example of a living organism from the world of biology—the study of life. BIOLOGY AND YOU Living in a small town, in the country, or at the edge of the suburbs, one may be lucky enough to hear an owl's hooting. This experience can lead to questions about where the bird lives, what it hunts, and how it finds its prey on dark, moonless nights. Biology, or the study of life, offers an organized and scientific framework for posing and answering such questions about the natural world. Biologists study questions about how living things work, how they interact with the environment, and how they change over time. Biologists study many different kinds of living things ranging from tiny organisms, such as bacteria, to very large organisms, such as elephants. Each day, biologists investigate subjects that affect you and the way you live. For example, biologists determine which foods are healthy. As shown in Figure 1-1, everyone is affected by this impor- tant topic. Biologists also study how much a person should exer- cise and how one can avoid getting sick. Biologists also study what CHARACTERISTICS OF LIFE The world is filled with familiar objects, such as tables, rocks, plants, pets, and automobiles. Which of these objects are living or were once living? What are the criteria for assigning something to the living world or the nonliving world? Biologists have established that living things share seven characteristics of life. These characteristics are organization and the presence of one or more cells, response to a stimulus (plural, stimuli), homeostasis, metabolism, growth and development, reproduction, and change through time. Organization and Cells Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world. For example, compare an owl to a rock. The rock has a spe- cific shape, but that shape is usually irregular. Furthermore, differ- ent rocks, even rocks of the same type, are likely to have different shapes and sizes. In contrast, the owl is an amazingly organized individual, as shown in Figure 1-2. Owls of the same species have the same body parts arranged in nearly the same way and interact with the environment in the same way. Copyright © by Holt, Rinehart and Winston. All rights reserved. ORGANISM (Barn Owl) ORGAN (Owl’s Ear) TISSUE (Nervous Tissue Within the Ear) CELL (Nerve Cell) your air, land, and fAll living organisms, whether made up of one cell or many cells, have some degree of organization. A cell is the smallest unit that can perform all life’s processes. Some organisms, such as bacteria, are made up of one cell and are called unicellular (YOON-uh-SEL-yoo-luhr) organisms. Other organisms, such as humans or trees, are made up of multiple cells and are called multicellular (MUHL-ti-SEL-yoo-luhr) organisms. Complex multicellular organisms have the level of orga- nization shown in Figure 1-2. In the highest level, the organism is made up of organ systems, or groups of specialized parts that carry out a certain function in the organism. For example, an owl’s ner- vous system is made up of a brain, sense organs, nerve cells, and other parts that sense and respond to the owl’s surroundings. Organ systems are made up of organs. Organs are structures that carry out specialized jobs within an organ system. An owl’s ear is an organ that allows the owl to hear. All organs are made up of tissues. Tissues are groups of cells that have similar abilities and that allow the organ to function. For example, nervous tissue in the ear allows the ear to detect sound. Tissues are made up of cells. A cell must be covered by a membrane, contain all genetic information necessary for replication, and be able to carry out all cell functions. Within each cell are organelles. Organelles are tiny structures that carry out functions necessary for the cell to stay alive. Organelles contain biological molecules, the chemical compounds that provide physical structure and that bring about movement, energy use, and other cellular functions. All biological molecules are made up of atoms. Atoms are the simplest particle of an ele- ment that retains all the properties of a certain element. Response to Stimuli Another characteristic of life is that an organism can respond to a stimulus—a physical or chemical change in the internal or external environment. For example, an owl dilates its pupils to keep the level of light entering the eye constant. Organisms must be able to respond and react to changes in their environment to stay alive. ORGANELLE (Mitochondrion) BIOLOGICAL MOLECULE (Phospholipid) ATOM (Oxygen) cell from the Latin, cella meaning “small room,” or “hut” Word Roots and Origins www.scilinks.org Topic: Characteristics of Life Keyword: HM60257 mb06se_bios01.qxd 5/18/07 10:37 AM Page 7 8 CHAPTER 1 Homeostasis All living things, from single cells to entire organisms, have mecha- nisms that allow them to maintain stable internal conditions. Without these mechanisms, organisms can die. For example, a cell’s water content is closely controlled by the taking in or releas- ing of water. A cell that takes in too much water will rupture and die. A cell that doesn’t get enough water will also shrivel and die. Homeostasis (HOH-mee-OH-STAY-sis) is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing. Organisms have regulatory systems that maintain internal conditions, such as temperature, water content, and uptake of nutrients by the cell. In fact, multi- cellular organisms usually have more than one way of maintain- ing important aspects of their internal environment. For example, an owl’s temperature is maintained at about 40°C (104°F). To keep a constant temperature, an owl’s cells burn fuel to produce body heat. In addition, an owl’s feathers can fluff up in cold weather. In this way, they trap an insulating layer of air next to the bird’s body to maintain its body temperature. Metabolism Living organisms use energy to power all the life processes, such as repair, movement, and growth. This energy use depends on metabolism (muh-TAB-uh-LIZ-uhm). Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment. For example, plants, algae, and some bacteria use the sun’s energy to generate sugar molecules during a process called photosynthesis. Some organisms depend on obtaining food energy from other organisms. For instance, an owl’s metabolism allows the owl to extract and modify the chemi- cals trapped in its nightly prey and use them as energy to fuel activities and growth. Growth and Development All living things grow and increase in size. Some nonliving things, such as crystals or icicles, grow by accumulating more of the same material of which they are made. In contrast, the growth of living things results from the division and enlargement of cells. Cell division is the formation of two new cells from an existing cell, as shown in Figure 1-3. In unicellular organisms, the primary change that occurs following cell division is cell enlargement. In multi- cellular life, however, organisms mature through cell division, cell enlargement, and development. Development is the process by which an organism becomes a mature adult. Development involves cell division and cell differen- tiation, or specialization. As a result of development, an adult organism is composed of many cells specialized for different func- tions, such as carrying oxygen in the blood or hearing. In fact, the human body is composed of trillions of specialized cells, all of which originated from a single cell, the fertilized egg. This unicellular organism, Escherichia coli, inhabits the human intestines. E. coli reproduces by means of cell division, during which the original cell splits into two identical offspring cells. FIGURE 1-3 Observing Homeostasis Materials 500 mL beakers (3), wax pen, tap water, thermometer, ice, hot water, goldfish, small dip net, watch or clock with a second hand Procedure 1. Use a wax pen to label three 500 mL beakers as follows: 27°C (80°F), 20°C (68°F), 10°C (50°F). Put 250 mL of tap water in each beaker. Use hot water or ice to adjust the tem- perature of the water in each beaker to match the temperature on the label. 2. Put the goldfish in the beaker of 27°C water. Record the number of times the gills move in 1 minute. 3. Move the goldfish to the beaker of 20°C water. Repeat observations. Move the goldfish to the beaker of 10°C. Repeat observations. Analysis What happens to the rate at which gills move when the temp- erature changes? Why? How do gills help fish maintain homeostasis? Quick Lab mb06se_bios01.qxd 5/18/07 10:37 AM Page 8 THE SCIENCE OF LIFE 9 Reproduction All organisms produce new organisms like themselves in a process called reproduction. Reproduction, unlike other characteristics, is not essential to the survival of an individual organism. However, because no organism lives forever, reproduction is essential for the continuation of a species. Glass frogs, as shown in Figure 1-4, lay many eggs in their lifetime. However, only a few of the frogs’ off- spring reach adulthood and successfully reproduce. During reproduction, organisms transmit hereditary informa- tion to their offspring. Hereditary information is encoded in a large molecule called deoxyribonucleic acid, or DNA. A short segment of DNA that contains the instructions for a single trait of an organism is called a gene. DNA is like a large library. It contains all the books—genes—that the cell will ever need for making all the struc- tures and chemicals necessary for life. Hereditary information is transferred to offspring during two kinds of reproduction. In sexual reproduction, hereditary information recombines from two organisms of the same species. The resulting offspring are similar but not identical to their parents. For example, a male frog’s sperm can fertilize a female’s egg and form a single fer- tilized egg cell. The fertilized egg then develops into a new frog. In asexual reproduction, hereditary information from different organisms is not combined; thus the original organism and the new organism are genetically the same. A bacterium, for example, reproduces asexually when it splits into two identical cells. Change Through Time Although individual organisms experience many changes during their lifetime, their basic genetic characteristics do not change. However, populations of living organisms evolve or change through time. The ability of populations of organisms to change over time is important for survival in a changing world. This factor is also impor- tant in explaining the diversity of life-forms we see on Earth today. 1. How does biology affect a person’s daily life? 2. How does biology affect society? 3. Name the characteristics shared by living things. 4. Summarize the hierarchy of organization found in complex multicellular organisms. 5. What are the different functions of homeostasis and metabolism in living organisms? 6. How does the growth among living and nonliv- ing things differ? 7. Why is reproduction an important characteristic of life? CRITICAL THINKING 8. Applying Information Crystals of salt grow and are highly organized. Why don’t biologists con- sider them to be alive? 9. Analyzing Models When a scientist designs a space probe to detect life on a distant planet, what kinds of things should it measure? 10. Making Comparisons Both cells and organisms share the characteristics of life. How are cells and organismsood supply will be like in the near future.EVOLUTION OF LIFE Individual organisms change during their lifetime, but their basic genetic characteristics do not change. However, populations of liv- ing organisms do change through time, or evolve. Evolution, or descent with modification, is the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop. Evolution as a theme in biology helps us understand how the various branches of the “tree of life” came into existence and have changed over time. It also explains how organisms alive today are related to those that lived in the past. Finally, it helps us understand the mechanisms that underlie the way organisms look and behave. Natural Selection The ability of populations of organisms to change over time is important for survival in a changing world. According to the theory of evolution by natural selection, organisms that have certain favorable traits are better able to survive and reproduce success- fully than organisms that lack these traits. One product of natural selection is the adaptation of organisms to their environment. Adaptations are traits that improve an indi- vidual’s ability to survive and reproduce. For example, rabbits with white fur and short ears in a snowy place, such as the one in Figure 1-7a, may avoid predators and frostbitten ears more often than those with dark fur and long ears. Thus, the next generation of rabbits will have a greater percentage of animals carrying the genes for white fur and short ears. In contrast, the brown, long- eared rabbit, as shown in Figure 1-7b, would survive and reproduce more successfully in a hot desert environment. The survival and reproductive success of organisms with favor- able traits cause a change in populations of organisms over gener- ations. This descent with modification is an important factor in explaining the diversity of organisms we see on Earth today. 1. Name three unifying themes found in biology. 2. How is the unity and diversity in the living world represented? 3. Identify the three domains and the kingdoms found in each domain. 4. How are organisms interdependent? 5. Describe why evolution is important in explain- ing the diversity of life. 6. Distinguish between evolution and natural selection. CRITICAL THINKING 7. Applying Information Assign the various top- pings you put on pizza to the appropriate domains and kingdoms of life. 8. Analyzing Graphics According to the “tree” in Figure 1-5, which of these pairs are more closely related: Archaea:Bacteria or Archaea:Eukarya? 9. Making Hypotheses Fossil evidence shows that bats descended from shrewlike organisms that could not fly. Write a hypothesis for how natural selection might have led to flying bats. SECTION 2 REVIEW (a) This short-eared arctic hare, Lepus arcticus, is hidden from predators and protected from frostbite in a snowy environment. (b) The mottled brown coats of desert rabbits blend in with the dirt and dry grasses, and their long ears help them radiate excess heat and thus avoid overheating. FIGURE 1-7 (a) (b) Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 13 TH E STUDY OF BIOLOGY Curiosity leads us to ask questions about life. Science provides a way of answering such questions about the natural world. Science is a systematic method that involves forming and testing hypotheses. More importantly, science relies on evidence, not beliefs, for drawing conclusions. SCIENCE AS A PROCESS Science is characterized by an organized approach, called the scientific method, to learn how the natural world works. The methods of science are based on two important principles. The first principle is that events in the natural world have natural causes. For example, the ancient Greeks believed that lightning and thunder occurred because a supernatural god Zeus hurled thunderbolts from the heavens. By contrast, a scientist considers lightning and thunder to result from electric charges in the atmos- phere. When trying to solve a puzzle from nature, all scientists, such as the one in Figure 1-8, accept that there is a natural cause to solve that puzzle. A second principle of science is uniformity. Uniformity is the idea that the fundamental laws of nature operate the same way at all places and at all times. For example, scientists assume that the law of gravity works the same way on Mars as it does on Earth. Steps of the Scientific Method Although there is no single method for doing science, scientific studies involve a series of common steps. 1. The process of science begins with an observation. An observation is the act of perceiving a natural occurrence that causes someone to pose a question. 2. One tries to answer the question by forming hypotheses (singular, hypothesis). A hypothesis is a proposed explanation for the way a particular aspect of the natural world functions. 3. A prediction is a statement that forecasts what would happen in a test situation if the hypothesis were true. A prediction is recorded for each hypothesis. 4. An experiment is used to test a hypothesis and its predictions. 5. Once the experiment has been concluded, the data are analyzed and used to draw conclusions. 6. After the data have been analyzed, the data and conclusions are communicated to scientific peers and to the public. This way oth- ers can verify, reject, or modify the researcher’s conclusions. SECTION 3 OBJECTIVES ● Outline the main steps in the scientific method. ● Summarize how observations are used to form hypotheses. ● List the elements of a controlled experiment. ● Describe how scientists use data to draw conclusions. ● Compare a scientific hypothesis and a scientific theory. ● State how communication in science helps prevent dishonesty and bias. VOCABULARY scientific method observation hypothesis prediction experiment control group experimental group independent variable dependent variable theory peer review All researchers, such as the one releasing an owl above, use the scientific method to answer the questions they have about nature. FIGURE 1-8 Copyright © by Holt, Rinehart and Winston. All rights reserved. 14 CHAPTER 1 OBSERVING AND ASKING QUESTIONS The scientific method generally begins with an unexplained observa- tion about nature. For example, people have noticed for thousands of years that owls can catch prey in near total darkness. As shown in steps and of Figure 1-9, an observation may then raise ques- tions. The owl observation raises the question: How does an owl detect prey in the dark? FORMING A HYPOTHESIS After stating a question, a biologist lists possible answers to a sci- entific question—hypotheses. Good hypotheses answer a question and are testable in the natural world. For example, as shown in step Figure 1-9, there are several possible hypotheses for the question of how owls hunt at night: (a) owls hunt by keen vision in the dark; (b) owls hunt by superb hearing; or (c) owls hunt by detecting the prey’s body heat. Predicting To test a hypothesis, scientists make a prediction that logically fol- lows from the hypothesis. A prediction is what is expected to hap- pen if each hypothesis were true. For example, if hypothesis (a) is true, (owls hunt by keen night vision) then one can predict that the owl will pounce only on the mouse in either a light or a dark room. If hypothesis (b) is true (owls hunt by hearing), then one can pre- dict that in a lighted room, the owl will pounce closer to the mouse’s head. But, in a dark room, the owl should pounce closer to a rustling leaf attached to the mouse. Finally, if hypothesis (c) is true (owls hunt by sensing body heat), then an owl would strike only the prey no matter the room conditions, because owls hunt by detecting the prey’s body heat. 3 1 2 Copyright © by Holt, Rinehart and Winston. All rights reserved. A scientific study includes observations, questions, hypotheses, predictions, experiments, data analysis, and conclu- sions. A biologist can use the scientific method to set up an experiment to learn how an owl captures prey at night. FIGURE 1-9 1 OBSERVATION Owls capture prey on dark nights. 2 QUESTION How do owls detect prey on dark nights? 3 HYPOTHESES a) Owls hunt in the dark by vision. b) Owls hunt in the dark by hearing. c) Owls hunt in the dark by sensing body heat. THE SCIENCE OF LIFE 15 Notice that these predictions make it difficult to distinguish be- tween the vision and body heat hypotheses. The reason is that both hypotheses predict that the owl could grab the mouse in a dark room. Also, these three hypotheses do not eliminate all other factors that could influence how the owl finds its prey. However, testing predictions can allow one to begin rejecting hypotheses and thus to get closer to determining the answer(s) to a question. DESIGNING AN EXPERIMENT Biologists often test hypotheses by setting up an experiment. Step in Figure 1-9 outlines an experiment to test the hypotheses about how an owl hunts at night. First, experimenters set up a room with an owl perch high on one side and a small trap door on the other side for releasing mice. Then, they tied a leaf to each mouse’s tail with a string and released each mouse into the room. Next, each mouse ran silently across the room, but the leaf trailed behind, making a rustling noise. During half of the trials, the lights were on. During the other half, the room was dark. Technicians videotaped all the action in the chamber with an infrared light, which owls cannot see. The researchers then viewed the videos and measured the position of the owl’s strike relative to each mouse’s head. Performing the Experiment Many scientists use a controlled experiment to test their hypotheses. A controlled experiment compares an experimental group and a control group and only has one variable. The control group pro- vides a normal standard against which the biologist can compare results of the experimental group. The experimental group is iden- tical to the control group except for one factor, the independent variable. The experimenter manipulates the independent variable, sometimes called the manipulated variable. 4 4 EXPERIMENT 5 DATA COLLECTION AND ANALYSIS Measure and compare the distance from the owl’s strike to the mouse and to the leaf in light and dark. 6 CONCLUSION Data supported the hearing hypothesis: Owls hunt in the dark by hearing. prey Test predictions of the three hypotheses. Control: In the light Experimental: In the dark 1 2 3 4 5 6 7 8 9 10 11 Predicting Results Materials 2 Petri dishes with agar, cellophane tape, wax pen Procedure 1. Open one of the Petri dishes, and streak your finger across the surface of the agar. 2. Replace the lid, and seal it with the tape. Label this Petri dish with your name and a number 1. 3. Seal the second Petri dish with- out removing the lid. Label this Petri dish with your name and the number 2. 4. Write a prediction about what will happen in each dish. Store your dishes as your teacher directs. Record your observations. Follow your teacher’s directions for disposal of your dishes. Analysis Was your prediction accurate? What evidence can you cite to support your prediction? If you did not obtain the results you predicted, would you change your testing method or your prediction? Explain. Evaluate the importance of obtaining a result that does not support your prediction. Quick Lab mb06se_bios03.qxd 5/18/07 10:40 AM Page 15 16 CHAPTER 1 The independent variable in the owl experiment is the presence or absence of light. In the owl experiment, the control group hunts in the light, and the experimental group hunts in the dark. In addi- tion to varying the independent variable, a scientist observes or measures another factor called the dependent variable, or respond- ing variable, because it is affected by the independent variable. In the owl experiment, the dependent variable is distance from the owl’s strike to the mouse’s head. Testing the Experiment Some controlled experiments are conducted “blind.” In other words, the biologist who scores the results is unaware of whether a given subject is part of the experimental or control group. This factor helps eliminate experimenter bias. Experiments should also be repeated, because living systems are variable. Moreover, scien- tists must collect enough data to find meaningful results. COLLECTING AND ANALYZING DATA Most experiments measure a variable—the dependent variable. This measurement provides quantitative data, data measured in numbers. For example, in the experiment above, scientists mea- sured the distance of an owl’s strike from the prey’s head in cen- timeters, as shown in step of Figure 1-9. An event’s duration in milliseconds is also an example of quantitative data. Biologists usually score the results of an experiment by using one of their senses. They might see or hear the results of an experiment. Scientists also extend their senses with a micro- scope for tiny objects or a microphone for soft sounds. In the owl experiment, biologists extended their vision with infrared cameras. Analyzing and Comparing Data After collecting data from a field study or an experiment and then organizing it, biologists then analyze the data. In analyzing data, the goal is to determine whether the data are reliable, and whether they support or fail to support the predictions of the hypothesis. To do so, scientists may use statistics to help determine relation- ships between the variables involved. They can then compare their data with other data that were obtained in other similar studies. It is also important at this time to determine possible sources of error in the experiment just per- formed. Scientists usually display their data in tables or graphs when analyzing it. For the owl study, biologists could have made a bar graph such as the one in Figure 1-10, which shows the average distance from the owl’s strike relative to the mouse’s head or the leaf in the light and in the dark. 5 5 0 10 15 20 25 In the light In the dark Average distance from strike (cm) Distance Between Owl Strike and a Mouse or From a Leaf Attached to Mouse 30 Mouse Leaf Mouse Leaf The data below are hypothetical results that might occur from the described owl experiment.The independent variable is the darkness of the room, and the dependent variable is how far the owl struck from the mouse’s head.The data show that the owl strikes more accurately at the mouse in the light but strikes more accurately at the leaf in the dark. FIGURE 1-10 Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 17 DRAWING CONCLUSIONS Biologists analyze their tables, graphs, and charts to draw conclu- sions about whether or not a hypothesis is supported, as shown in step of Figure 1-9. The hypothetical owl data show that in the light, owls struck with greater accuracy at the mouse than at the leaf, but in the dark, owls struck with greater accuracy at the leaf than the mouse. Thus, the findings support the hearing hypothe- sis, but not the vision hypothesis. An experiment can only disprove, not prove, a hypothesis. For example, one cannot conclude from the results that the hearing hypothesis is proven to be true. Perhaps the owl uses an unknown smell to strike at the mouse. One can only reject the vision hypothe- sis because it did not predict the results of the experiment correctly. Acceptance of a hypothesis is always tentative in science. The scientific community revises its understanding of phenomena, based on new data. Having ruled out one hypothesis, a biologist will devise more tests to try to rule out any remaining hypotheses. Making Inferences Scientists often draw inferences from data gathered during a field study or experiment. An inference (IN-fuhr-uhns) is a conclusion made on the basis of facts and previous knowledge rather than on direct observations. Unlike a hypothesis, an inference is not directly testable. In the owl study, it is inferred that the owl detects prey from a distance rather than by direct touch. Applying Results and Building Models As shown in Figure 1-11, scientists often apply their findings to solve practical problems. They also build models to represent or describe things. For example in 1953, James Watson and Francis Crick used cardboard balls and wire bars to build physical models of atoms in an attempt to understand the structure of DNA. Mathematical models are sets of equations that describe how dif- ferent measurable items interact in a system. The experimenter can adjust variables to better model the real-world data. CONSTRUCTING A THEORY When a set of related hypotheses is confirmed to be true many times, and it can explain a great amount of data, scientists often reclassify it as a theory. Some examples include the quantum the- ory, the cell theory, or the theory of evolution. People commonly use the word “theory” in a different way than scientists use the word. People may say “It’s just a theory” suggesting that an idea is untested, but scientists view a theory as a highly tested, generally accepted principle that explains a vast number of observations and experimental data. 6 Copyright © by Holt, Rinehart and Winston. All rights reserved. Biologists often apply their knowledge of the natural world to practical problems. Studies on the owl’s keen ability to locate sounds in space despite background noise are helping biotechnologists and bioengineers develop better solutions for people with impaired hearing, such as the people shown in this picture. FIGURE 1-11 18 CHAPTER 1 COMMUNICATING IDEAS An essential aspect of scientific research is scientists working together. Scientists often work together in research teams or sim- ply share research results with other scientists. This is done by publishing findings in scientific journals or presenting them at sci- entific meetings, as shown in Figure 1-12. Sharing information allows others working independently to verify findings or to con- tinue work on established results. For example, Roger Payne pub- lished the results of his owl experiments in a journal in 1971. Then, other biologists could repeat it for verification or use it to study the mechanisms introduced by the paper. With the growing impor- tance of science in solving societal issues, it is becoming increas- ingly vital for scientists to be able to communicate with the public at large. Publishing a Paper Scientists submit research papers to scientific journals for publica- tion. A typical research paper has four sections. First, the Introduction poses the problem and hypotheses to be investigated. Next, the Materials and Methods describe how researchers proceeded with the experiment. Third, the Results state the findings the experiment presented, and finally, the Discussion gives the significance of the experiment and future directions the scientists will take. Job Description Forensic biolo- gists are scientists who study biological materials to investigate potential crimes and other legal issues against humans and animals. Forensic scientists have knowledge in areas of biology, such as DNA and blood pattern analysis, and work in private sector and public laboratories. Focus On a Forensic Biologist As a law enforcement forensic specialist for the Texas Parks and Wildlife Department, Beverly Villarreal assists the game warden in investigations of fish and wildlife violations, such as illegal hunting and fishing. Villarreal analyzes blood and tissue samples to identify species of animals such as fish, birds, and reptiles. Her work helps game wardens as they enforce state laws regarding hunting and fishing. Most people think of forensic scientists as the glamorous crime investigators on TV, but according to Villarreal real forensic scientists “spend a great deal of time at a lab bench running analysis after analysis.” Many of the methods used in animal forensics, such as DNA sequenc- ing, are also used in human forensics. Education and Skills • High school—three years of science courses and four years of math courses. • College—bachelor of science in biol- ogy, including course work in zoology and genetics, plus experience in per- forming DNA analyses. • Skills—patience, attention to detail, and ability to use fine tools. Careers in BIOLOGY Forensic Biologist For more about careers, visit go.hrw.com and type in the keyword HM6 Careers. www.scilinks.org Topic: Scientific Investigations Keyword: HM61358 mb06se_bios03.qxd 5/18/07 10:40 AM Page 18 THE SCIENCE OF LIFE 19 1. What two principles make the scientific method a unique process? 2. Define the roles of observations and hypotheses in science. 3. Summarize the parts of a controlled experiment. 4. Summarize how we make conclusions about the results of an experiment. 5. Why is the phrase, “it’s just a theory” misleading? 6. Give another example of a conflict of interest. CRITICAL THINKING 7. Making Hypotheses On a nocturnal owl’s skull, one ear points up, and the other ear points down. Suggest a hypothesis for this observation. 8. Designing Experiments Design an experiment to establish if owls hunt by keen sight or hunt by heat seeking. 9. Calculating Information What was the average distance between the owl’s strike and the mouse if the recorded differences in this experiment were 25, 22, 19, 19, and 15? SECTION 3 REVIEW After scientists submit their papers to a scientific journal, the editors of that journal will send the paper out for peer review. In a peer review, scientists who are experts in the field anonymously read and critique that research paper. They determine if a paper pro- vides enough information so that the experiment can be duplicated and if the author used good experimental controls and reached an accurate conclusion. They also check if the paper is written clearly enough for broad understanding. Careful analysis of each other’s research by fellow scientists is essential to making scientific progress and preventing scientific dishonesty. HONESTY AND BIAS The scientific community depends on both honesty and good sci- ence. While designing new studies, experimenters must be very careful to prevent previous ideas and biases from tainting both the experimental process and the conclusions. Scientists have to keep in mind that they are always trying to disprove their favorite ideas. Scientists repeat experiments to verify previous findings. This allows for science to have a method for self-correction and it also keeps researchers honest and credible to their peers in the field. Conflict of Interest For most scientists, maintaining a good reputation for collecting and presenting valid data is more important than temporary prestige or income. So, scientists try to avoid any potential conflicts of interest. For example, a scientist who owns a biotechnology company and manufactures a drug would not be the best researcher to critically test that drug’s safety and effectiveness. To avoid this potential con- flict of interest, the scientist allows an unaffected party, such as a research group, to test the drug’s effectiveness. The threat of a potential scandal based on misleading data or conclusions is a pow- erful force in science that helps keep scientists honest and fair. Scientists present their experiments in various forms. The scientists above are presenting their work in the form of a poster at a scientific meeting. FIGURE 1-12 Copyright © by Holt, Rinehart and Winston. All rights reserved. The Internet can provide a wealth of scientific information for a report, but the information may not always be credible or accurate. You can use the methods above to check the accuracy and credibility of your sources. SCIENCE TECHNOLOGY SOCIETY SCIENCE ON THE INTERNET: A New Information Age I n the past, students research- ing a science topic would typ- ically begin their research by visiting a library to use printed reference materials, such as encyclopedias. Today, most stu- dents research topics by using a computer and searching for information on the Internet. The Internet can provide students with a wealth of infor- mation. But which Web sites have accurate information, and which Web sites do not? Checking Web Addresses Students should use the Web address, or URL, to establish the Web site’s credibility. Usually, the domain name can suggest who has published the Web site. Web sites can be pub- lished by governmental agen- cies (ends in “dot gov” or .gov), by educational institutions (ends in “dot edu” or .edu), by organizations (ends in “dot org” or .org), or by commercial businesses (ends in “dot com” or .com). Government Web sites are usually reliable. Examples of credible governmental Web sites are the National Institutes of Health (NIH) and the Food and Drug Administration (FDA). University and medical school sites are also reliable sources of information. Many organiza- tions that research and teach the public about specific diseases and conditions can also provide reliable information. Examples of such organizations are the American Cancer Society and the American Heart Association. Evaluating Web Sites The credibility of the author of the Web site should also be checked. Make sure the author is not trying to sell anything and is established in his or her field. For example, a health Web site’s author should be a med- ical professional. It is also important to check the date that the information was posted on the Web to ensure that the information is current. Also, the Web site should provide ref- erences from valid sources, such as scientific journals or govern- ment publications. Finally, the student should always double-check informa- tion between several reliable Web sites. If two or three reliable sites provide the same informa- tion, the student can feel confi- dent in using that information. Web Sites for Students The Internet Connect boxes in this textbook have all been reviewed by professionals at the National Science Teachers Association (NSTA). Students can trust that these sites are reliable sources for science- or health-related topics. REVIEW 1. Which types of Web addresses are the most reliable? 2. List four important features to evaluate when using a Web site for research. 3. Supporting Reasoned Opinions Why do you think a Web site that is advertising a product may not offer accurate information? REVIEW 20 www.scilinks.org Topic: Using the Internet Keyword: HM61589 mb06se_biosts.qxd 5/18/07 10:42 AM Page 20 TOOLS AND TECHNIQUES With proper equipment and good methods, biologists can see, manipulate, and understand the natural world in new ways. Microscopes are one of many useful tools used to unlock nature’s biological secrets. MICROSCOPES AS TOOLS Tools are objects used to improve the performance of a task. Microscopes are tools that extend human vision by making enlarged images of objects. Biologists use microscopes to study organisms, cells, cell parts, and molecules. Microscopes reveal details that otherwise might be difficult or impossible to see. Light Microscopes To see small organisms and cells, biologists typically use a light microscope, such as the one shown in Figure 1-13. A compound light microscope is a microscope that shines light through a spec- imen and has two lenses to magnify an image. To use this micro- scope, one first mounts the specimen to be viewed on a glass slide. The specimen must be thin enough for light to pass through it. For tiny pond organisms, such as the single-celled paramecium, light passing through the organism is not a problem. For thick objects, such as plant stems, biologists must cut thin slices for viewing. There are four major parts of a compound light microscope. For further description of the parts of a micro- scope, see the Appendix. 1. Eyepiece The eyepiece (ocular (AHK-yoo-luhr) lens) magnifies the image, usually 10 times. 2. Objective Lens Light passes through the specimen and then through the objective lens, which is located directly above the specimen. The objective lens enlarges the image of the specimen. Scientists sometimes use stains to make the image easier to see. 3. Stage The stage is a platform that supports a slide holding the specimen. The slide is placed over the opening in the stage of the microscope. 4. Light Source The light source is a light bulb that provides light for viewing the image. It can be either light reflected with a mirror or an incandescent light from a small lamp. SECTION 4 OBJECTIVES ● List the function of each of the major parts of a compound light microscope. ● Compare two kinds of electron microscopes. ● Describe the importance of having the SI system of measurement. ● State some examples of good laboratory practice. VOCABULARY compound light microscope eyepiece (ocular lens) objective lens stage light source magnification nosepiece resolution scanning electron microscope transmission electron microscope metric system base unit Compound light microscopes open the human eye to an interesting world including tiny pond organisms, healthy and diseased cells, and the functioning of cell parts. FIGURE 1-13 Objective lens Eyepiece (ocular lens) Stage Light THE SCIENCE OF LIFE 21 Copyright © by Holt, Rinehart and Winston. All rights reserved. 22 CHAPTER 1 Magnification and Resolution Microscopes vary in powers of magnification and resolution. Magnification is the increase of an object’s apparent size. Revolving the nosepiece, the structure that holds the set of objective lens, rotates these lenses into place above the specimen. In a typical com- pound light microscope, the most powerful objective lens produces an image up to 100 times (100) the specimen’s actual size. The degree of enlargement is called the power of magnification of the lens. The standard ocular lens magnifies a specimen 10 times (10). To compute the power of magnification of a microscope, the power of magnification of the strongest objective lens (in this case, 100) is multiplied by the power of magnification of the ocular lens (10). The result is a total power of magnification of 1000. Resolution (REZ-uh-LOO-shuhn) is the power to show details clearly in an image. The physical properties of light limit the ability of light microscopes to resolve images, as shown in Figure 1-14a. At pow- ers of magnification beyond about 2,000, the image of the speci- men becomes fuzzy. For this reason, scientists use other microscopes to view very small cellsPlease create English vocabulary fill-in-the-blank quiz questions for the following English words. . accept
各acceptance
acceptable
2. achieve lativ」完成；達到
【91學測】
名 achievement達成；成就
形 achievable可完成的；做得成的
3. adopt la'dapt」收養；採納【88、97學測】
相似 adapt 動（使）適應；改編
4. agree la'gril同意 （with / to)
{F施5-10）
名 agreement一致；協議
IF M5-10;
形 agreeable同意的
(F NE5-10;
片語 agree with +人/to +事情同意〜
5.allow [alau] 九許；給予(F2-2,F地1-5,L1-93
名 allowance津貼；零用錢
6. announce lanaunsl 宣布
F5-1？192學測〕
名 announcement宣告；通告
F5-1
7. appear [a prr] 出現；呈現；似乎
各 appearance顯露；出現；外表
8. apply laplar] 申請；應用【94學測】
冬 application申請（書）；用途；敷用
多 appliance 工具；用具；器具【97學測】
冬 applicant 申請人
片語 apply A to B 應用A於B
apply for 申請~
9. assume lasiuml 假定
留 assumption 假設；假裝；擔任
片語 assuming = if (that) +S+V...
10. assure [arur] 確保；保證（of)
（F #2-11,L4-4}【104學測，99指考】
名 assurance IU」自信； 保險[C］保證
11. attend la'tend」 出席：照料
2-5,S1-9}
客 attendance到場；出席人數
片語 attend to + 0 注意〜
12. bear [ber」 承受；忍耐：具有
{饰3-12}
相似 stand 動 忍受
13. cause ［koz］ 引起；起因（n.）；原則目
標（n.） = lead to = bring about
14. choose [tuz」 挑選；選擇
F1-2}
(chose • chosen)
15. claim [kleml 要求；奪走；聲稱 （n.)
{L4-10,S1-11;【99學測】
16. collapse ［kalleps」 倒塌；崩潰
【88、89、102學測】
形 collapsed 崩潰的
17. complete [kam plit」完成
{F5-1,F5-2}
各 completion LU完成；結束
SI 98B9 .08
形 complete完全的：澈底的
18. concern [kan'ssn］涉及；關心；憂慮；
關心的事 （n.)；擔心（n.)
【87學測】
concerning = regarding 關於
{L5-6}
片語 be concered about 擔心~
19. consider [kan'srdal考慮；認為
各 considerationIUI體貼；考慮
形 considerable相當多的；非常【90學測】
形 considerate體貼的；考慮周全的
【100學測，91指考】
1S5-1) 20. contain 「kan'tenl包含；容納：控制
{F4-4,F能1-7,L1-12,S2-6}【99學測！
各 container容
【100學測】
(L4-1,53-91 21. create [krret』創造；創作
{F1-9,F3-5,F4-9,F街1-12,S2-9}
名 creation 創造：產物；天地萬物
形 creative 有創造力的；獨創的
各 creativity 創造力Caractéristiques générales de la synthèse de documents La synthèse est un exercice assez simple, car très technique. Pour réussir, il faut néanmoins faire preuve de rigueur car elle est très codifiée. Les pièges de la synthèse La plupart des étudiants ignorent la technique de synthèse telle qu’elle est attendue en BTS. Aussi plusieurs pièges sont à éviter. La synthèse n’est pas une dissertation personnelle Premier écueil : si l’on se souvint de la consigne vue plus avant, le travail demandé doit être objectif. Aucun point de vue personnel ou même appréciation subjectif sur les documents ne doit apparaître dans la rédaction. On recommande d’ailleurs aux étudiants de ne pas utiliser le pronom « je » dans leur travail de façon à éviter tout malentendu. Le candidat doit donc rapporter les idées des auteurs de façon neutre, sans jugement de valeur. La synthèse n’est pas un résumé des documents La plus grande erreur commise en première année de BTS consiste à résumer les documents, les uns après les autres. Un petit détour par l’étymologie nous permettra de mieux comprendre le travail attendu. Le terme « synthèse » vient du grec sunthesis qui signifie « mise en commun ». Il s’agit donc de rassembler les informations collectées dans les différents documents en un ensemble organisé, donc cohérent. Les idées doivent être confrontées en établissant des liens entre les documents. La synthèse n’est pas un montage de citations Le Bac de français est derrière vous. Oubliez (en partie) cette épreuve. Ici, pas de citations, de numéros de lignes pour appuyer votre rédaction. Votre travail consiste à reformuler de façon synthétique le contenu et les enjeux des documents. La nature du travail demandé Une consigne codifiée pour rédiger votre synthèse Trois adjectifs dans cette consigne. Tout d’abord, la synthèse doit être concise, c’est-à-dire courte et dense. Quatre pages maximum sont généralement attendues à l’épreuve. Nous l’avons déjà évoqué plus haut, la synthèse est un exercice absolument objectif. Aucune idée extérieure aux documents ni commentaire personnel ne doivent figurer dans la rédaction. Enfin, la synthèse est un travail ordonné. Un plan soutient donc la rédaction, on attend ainsi : • une introduction; • un développement; • une conclusion. La démarche à adopter pour votre synthèse La préparation de la synthèse se décompose en deux temps : • Un premier temps consacré à la lecture active de chaque document. Les idées importantes sont relevées, les arguments sont listés, le raisonnement de l’auteur est analysé. • Un second temps consacré à la mise en relation des différents documents de façon à établir des liens entre eux : il s’agit en fait de recomposer un débat entre les auteurs. Sont-ils d’accord ? S’opposent-ils ? Si oui sur quels point ? … La synthèse : un acte de communication On veut donc vérifier que vous savez « lire » : c’est-à-dire que vous êtes capable de comprendre ce qui est écrit dans les documents et de reformuler selon des contraintes de longueur de texte. L’étymologie du verbe « lire » nous le confirme : legere, en latin, signifique « choisir » La méthodologie de synthèse en 10 points Voici un récapitulatif des 10 maladresses principales à éviter et des 10 règles à adopter Les interdits de la synthèse 1. Faire des citations des auteurs des documents pour soutenir les idées avancées. 2. Donner son avis, émettre des remarques subjectives : ex : l’auteur oublie malheureusement que… 3. Faire des références à des documents hors corpus, faire allusion à une autre œuvre de l’auteur. 4. Rédiger un « catalogue » des idées sans lien logique entre elles. Rédiger au fil de son inspiration. 5. Rédiger une synthèse longue et détaillée. 6. Laisser de côté un document, parce que l’on ne l’a pas compris ou qu’il nous semble inintéressant… 7. Utiliser le pronom « je ». 8. Faire un plan apparent (A, B…) avec des titres. 9. Juxtaposer des résumés des documents. 10. Faire référence aux documents par le numéro attribué dans le dossier. Ce qu’il faut faire 1. Reformuler les idées. 2. Rester neutre, objectif. 3. Ne traiter que les documents proposés. 4. Traiter les idées selon un plan précis. 5. Quatre pages maximum 6. Traiter tous les documents, même de façon inégale, certains documents sont plus « riches » en idées que d’autres. 7. Préférer le « on » ou le « nous ». 8. Rédiger sans titres avec des phrases de transition. 9. Confronter les idées communes aux documents. 10. Faire référence aux documents par le nom de l’auteur et l’initiale du prénom. Si ces 10 règles sont respectées, une importante partie de la méthode est acquise ! L'évaluation du travail de synthèse On se rappelle que cette épreuve est notée sur 40 points. En règle générale, les correcteurs adoptent le barème suivant qui vise à valider 4 grandes compétences, chacune notée sur 40 points. Comprendre les documents Ces 10 premiers points valident vos compétences de lecture : Les idées essentielles ont-elles été bien relevées ? Tous les documents ont-ils été bien compris ? L’unité thématique des documents doit apparaître ans le traitement des informations collectées. Confronter Le correcteur vérifiera notamment que tous les documents ont bien été exploités, qu’aucune « impasse » n’a été faite. Il sanctionnera, le cas échéant, l’ajout d’idées extérieures. Certains étudiants pensent que l’introduction d’idées extérieures vient enrichir leur travail et montre leur connaissance du sujet. Il faudra attendre l’épreuve d’écriture personnelle pour le faire. Ici, rappelons-le, seuls les documents proposés à l’étude figurent dans la synthèse. La confrontation des idées sera également évaluée : Le candidat a-t-il établi des liens entre les idées des auteurs ? Chaque partie de la rédaction repose-t-elle sur plusieurs documents ? Structurer Quelle que soit la logique suivie, la synthèse suit un plan. Introduction et conclusion doivent apparaître clairement. La rédaction suit une ligne directrice et un parcours. Les documents sont référencés, l’ensemble est organisé. Utilisez des connecteurs logiques pour lier les parties entre elles. Ils faciliteront grandement la lecture et la progression de vos idées sera plus claire. Rédiger & reformuler Une expression écrire claire est attendue. Elle respecte les normes et usages de la langue écrite courante. La richesse du vocabulaire sera valorisée. Le tout est rédigé : pas de tirets, de titres ou de tissage de citations. Les propos des auteurs sont reformulés, on sanctionnera ici toute formulation d’appréciations personnelles.SOAL 1. Dalam Islam, tawuran termasuk perbuatan yang… A. Dianjurkan jika untuk membela teman B. Boleh dilakukan jika merasa benar C. Dilarang karena merugikan banyak pihak D. Wajib jika ada yang memulai E. Diperbolehkan dalam keadaan tertentu 2. Yang dimaksud dengan zina hati adalah… A. Perbuatan zina secara langsung B. Keinginan dan niat dalam hati terhadap hal yang dilarang C. Perkataan kasar kepada orang lain D. Perbuatan mencuri E. Melakukan ibadah dengan ikhlas 3. Salah satu faktor seseorang melakukan pacaran adalah... A. Tekanan ekonomi B. Rasa ketertarikan C. Kewajiban keluarga D. Tuntutan sekolah E. Peraturan pemerintah 4. Dalam konteks pembagian zina anggota tubuh (zina kecil), yang dimaksud dengan "zina tangan" secara spesifik adalah... a. Menggunakan tangan untuk mengambil barang yang bukan haknya. b. Memukul orang lain hingga terluka karena marah. c. Menyentuh atau memegang lawan jenis yang bukan mahram dengan sengaja. d. Menuliskan kata-kata kasar atau fitnah di media sosial. e. Memberikan bantuan kepada orang yang berniat melakukan maksiat. 5. Seorang remaja mulai merokok karena ingin diterima dalam kelompok pergaulannya. Jika dilihat dari sudut pandang pengambilan keputusan, tindakan yang paling tepat adalah… A. Mengikuti kebiasaan kelompok agar tidak dikucilkan B. Menolak dengan tegas dan mencari lingkungan yang lebih sehat C. Mencoba sekali saja agar tidak penasaran D. Diam saja tanpa mengambil sikap E. Ikut merokok tetapi diam-diam 6. Zina kaki terjadi ketika seseorang… A. Menggunakan kaki untuk bekerja B. Melangkah menuju hal yang dilarang agama C. Berjalan santai di taman D. Pergi ke tempat umum E. Mengantar teman pulang 7. Menurut hadits Nabi SAW, zina mata dilakukan dengan cara... A. Mendengar hal-hal yang haram B. Berbicara tentang lawan jenis C. Melihat lawan jenis yang bukan mahram dengan syahwat D. Memikirkan hal-hal kotor E. Meraba lawan jenis 8. Tawuran bertentangan dengan ajaran Islam karena tidak mencerminkan sikap… A. Sombong B. Sabar dan menahan amarah C. Malas D. Boros E. Takut 9. Contoh zina hati adalah… A. Membantu orang tua B. Berniat melakukan perbuatan maksiat C. Belajar dengan sungguh-sungguh D. Menjaga lisan dari kata-kata buruk E. Bersedekah kepada yang membutuhkan 10. Kurangnya perhatian dari keluarga dapat menyebabkan remaja... A. Menjadi lebih mandiri tanpa pengaruh B. Mencari kenyamanan melalui pacaran C. Menghindari semua pergaulan D. Lebih fokus belajar E. Menjadi pemimpin 11. Rasulullah SAW bersabda bahwa setiap anak Adam telah ditentukan bagian zinanya yang tidak bisa tidak akan dialaminya. Dalam hadits tersebut, Rasulullah menegaskan bahwa "zina tangan adalah..." a. Menunjuk b. Menggenggam c. Menulis d. Menyentuh e. Memberi 12. Perhatikan pernyataan berikut: (1) Tekanan teman sebaya (2) Kurangnya pengawasan orang tua (3) Rasa ingin tahu tinggi (4) Prestasi akademik yang baik Faktor utama yang mendorong remaja terjerumus dalam pergaulan bebas dan merokok ditunjukkan oleh nomor… A. (1), (2), dan (3) B. (1), (2), dan (4) C. (2), (3), dan (4) D. (1) dan (4) saja E. (3) dan (4) saja 13. Perilaku zina kaki harus dihindari karena… A. Membuat tubuh lelah B. Termasuk perbuatan dosa C. Mengurangi waktu istirahat D. Membuat kaki sakit E. Menghambat aktivitas 14. Zina mata termasuk dalam kategori perbuatan yang... A. Diperbolehkan jika tidak sengaja B. Dosa besar dan wajib dihindari C. Merupakan dosa kecil D. Biasa saja dan tidak berdampak E. Dapat dihapus dengan sedekah saja 15. Berikut ini yang merupakan dampak negatif dari tawuran adalah… A. Menambah teman baru B. Mendapat pujian dari masyarakat C. Terjalin persatuan D. Menimbulkan kerusakan dan korban E. Meningkatkan prestasi 16. Perbedaan zina hati dan zina fisik adalah… A. Zina hati lebih berat dari zina fisik B. Zina fisik tidak berdosa C. Zina hati hanya dalam pikiran/perasaan, sedangkan zina fisik dalam perbuatan D. Keduanya tidak ada hubungan E. Zina hati tidak perlu dihindari 17. Seorang siswa mulai berpacaran karena semua temannya melakukannya. Faktor utama yang memengaruhi adalah... A. Media sosial B. Rasa penasaran C. Lingkungan pergaulan D. Kurangnya aturan sekolah E. Pendidikan agama 18. Al-Qur'an Surah Al-Isra ayat 32 melarang umat Islam untuk "mendekati zina". Bagaimana kaitan larangan "mendekati" tersebut dengan perbuatan zina tangan? a. Zina tangan hanya dilarang jika dilakukan oleh mereka yang sudah menikah. b. Zina tangan dianggap sebagai salah satu pintu atau perantara yang dilarang karena dapat mengarah pada zina besar. c. Ayat tersebut hanya melarang zina besar, sedangkan zina tangan hanya dianggap makruh. d. Larangan tersebut hanya berlaku jika sentuhan tangan dilakukan di tempat yang sepi. e. Zina tangan tidak termasuk dalam cakupan ayat tersebut karena tidak melibatkan persetubuhan. 19. Seorang siswa mengetahui bahwa temannya sering merokok di lingkungan sekolah. Sikap yang paling mencerminkan tanggung jawab sosial adalah… A. Membiarkannya karena itu urusan pribadi B. Ikut mencoba agar memahami perasaan teman C. Menegur dengan baik dan melaporkan kepada pihak sekolah D. Menjauhi tanpa alasan yang jelas E. Menyebarkan kabar tersebut ke teman lain 20. Seseorang yang sengaja pergi ke tempat maksiat berarti… A. Melakukan kebaikan B. Melakukan zina hati C. Melakukan zina kaki D. Melakukan ibadah E. Tidak melakukan apa-apa 21. Contoh perilaku zina mata dalam kehidupan sehari-hari adalah... A. Menundukkan pandangan saat bertemu lawan jenis B. Membaca Al-Qur'an C. Menonton film porno atau tayangan aurat D. Menghadiri majelis ilmu E. Melihat pemandangan alam 22. Cara menghindari tawuran menurut ajaran Islam adalah… A. Membalas jika diserang B. Ikut-ikutan teman C. Menyelesaikan masalah dengan musyawarah D. Membentuk kelompok untuk melawan E. Menghindari semua orang 23. Cara menghindari zina hati adalah… A. Mengikuti hawa nafsu B. Membiarkan pikiran bebas C. Menjaga pandangan dan memperkuat iman D. Mengabaikan nasihat agama E. Bergaul bebas tanpa batas 24. Jika seorang siswa mengalami stres akibat hubungan pacaran, dampak yang paling tepat adalah... A. Meningkatnya prestasi belajar B. Hubungan sosial menjadi lebih baik C. Tekanan emosional dan mental D. Menjadi lebih disiplin E. Lebih fokus pada tujuan hidup 25. Terdapat sebuah hadits yang memberikan peringatan keras bahwa ditusuknya kepala seseorang dengan pasak/jarum besi lebih baik baginya daripada menyentuh wanita yang tidak halal baginya. Pelajaran utama dari kerasnya ancaman ini adalah... a. Syariat Islam menetapkan hukuman fisik bagi pelaku zina tangan di dunia. b. Menyentuh lawan jenis yang bukan mahram adalah dosa kecil yang mudah dihapuskan. c. Besarnya bahaya fitnah dari sentuhan fisik sehingga Islam menutup rapat celah tersebut dengan peringatan yang sangat berat. d. Ancaman tersebut hanya berlaku bagi kaum laki-laki dan tidak berlaku bagi wanita. e. Perbuatan tersebut hanya dilarang jika dilakukan dengan niat ingin melamar. 26. Dampak jangka panjang dari kebiasaan merokok bagi remaja tidak hanya pada kesehatan, tetapi juga kehidupan sosial. Contoh dampak sosial yang tepat adalah… A. Meningkatkan rasa percaya diri B. Memperluas jaringan pertemanan C. Menurunkan kepercayaan orang lain D. Membuat lebih fokus belajar E. Menambah energi dalam aktivitas 27. Sikap yang benar untuk menghindari zina kaki adalah… A. Mengikuti teman ke tempat negatif B. Membiasakan diri pergi ke tempat baik C. Mendatangi tempat maksiat D. Tidak peduli ke mana kaki melangkah E. Pergi ke tempat yang merugikan diri 28. Perhatikan pernyataan berikut! (1) Memandang lawan jenis dengan kagum (2) Melihat foto yang tidak menutup aurat (3) Menundukkan pandangan (ghadhul bashar) (4) Menonton adegan mesra di media sosial (5) Tidak sengaja melihat lawan jenis Yang termasuk contoh zina mata ditunjukkan oleh nomor... A. (1), (2), dan (3) B. (2), (3), dan (4) C. (1), (2), dan (4) D. (3), (4), dan (5) E. (1), (3), dan (5) KUNCI JAWABAN 1. C 2. B 3. B 4. C 5. B 6. B 7. C 8. B 9. B 10. B 11. D 12. A 13. B 14. C 15. D 16. C 17. C 18. B 19. C 20. C 21. C 22. C 23. C 24. C 25. C 26. C 27. B 28. C1. Apa yang dimaksud dengan prinsip penilaian dalam pembelajaran Bahasa dan Sastra Indonesia? A. Penentuan standar minimal kelulusan siswa B. Pendekatan yang digunakan untuk mengukur hasil belajar siswa C. Dasar-dasar yang harus dipenuhi dalam melaksanakan penilaian secara adil dan efektif D. Metode yang digunakan guru untuk memberikan tugas kepada siswa Jawaban: C 2. Salah satu prinsip penting dalam penilaian adalah "keseluruhan." Prinsip ini berarti bahwa penilaian harus: A. Dilakukan di akhir periode pembelajaran B. Melibatkan semua aspek yang dipelajari siswa, baik kognitif, afektif, maupun psikomotor C. Hanya mengukur pengetahuan dasar siswa D. Mengutamakan penilaian sikap dan perilaku siswa Jawaban: B 3. Prinsip "objektivitas" dalam penilaian mengacu pada: A. Menggunakan alat penilaian yang tepat dan relevan dengan materi pembelajaran B. Memberikan nilai berdasarkan hasil yang nyata tanpa dipengaruhi faktor lain seperti preferensi pribadi C. Melibatkan seluruh aspek pembelajaran dalam proses penilaian D. Menilai kemampuan siswa secara subyektif sesuai dengan kondisi kelas Jawaban: B 4. Manakah dari berikut ini yang merupakan salah satu prinsip penilaian yang baik dalam pembelajaran Bahasa dan Sastra Indonesia? A. Penilaian bersifat subyektif sesuai keinginan guru B. Penilaian dilakukan hanya berdasarkan satu aspek keterampilan siswa C. Penilaian dilakukan secara berkelanjutan untuk memantau perkembangan siswa D. Penilaian hanya dilakukan pada akhir semester Jawaban: C 5. Apa yang dimaksud dengan acuan penilaian dalam konteks pembelajaran Bahasa dan Sastra Indonesia? A. Sistem yang digunakan untuk memberikan umpan balik kepada siswa B. Kriteria atau standar yang digunakan untuk menentukan tingkat pencapaian siswa C. Teknik mengajar yang diterapkan selama proses pembelajaran D. Metode evaluasi lisan dalam menilai kemampuan berbicara siswa Jawaban: B 6. Acuan penilaian yang menggunakan kriteria tertentu sebagai patokan disebut: A. Acuan norma B. Acuan kriteria C. Acuan standar D. Acuan individual Jawaban: B 7. Penilaian yang membandingkan hasil belajar siswa dengan hasil belajar siswa lain dalam satu kelompok disebut: A. Penilaian berbasis kriteria B. Penilaian sumatif C. Penilaian berbasis norma D. Penilaian formatif Jawaban: C 8. Acuan kriteria dalam penilaian berarti bahwa penilaian: A. Menggunakan hasil belajar siswa lain sebagai standar B. Membandingkan pencapaian siswa dengan standar atau tujuan pembelajaran yang telah ditentukan C. Hanya menilai aspek kognitif siswa D. Dilakukan secara acak tanpa kriteria tertentu Jawaban: B 9. Prinsip "validitas" dalam penilaian berarti bahwa: A. Instrumen penilaian mengukur apa yang seharusnya diukur B. Penilaian dilakukan berdasarkan standar yang berubah-ubah C. Penilaian dilakukan hanya sekali dalam satu periode belajar D. Hasil penilaian dapat direplikasi oleh guru lain Jawaban: A 10. Salah satu contoh penerapan acuan kriteria dalam penilaian Bahasa dan Sastra Indonesia adalah: A. Membandingkan nilai siswa dengan nilai rata-rata kelas B. Menggunakan rubrik penilaian untuk menilai esai siswa berdasarkan standar tertentu C. Memberikan nilai berdasarkan partisipasi siswa selama pembelajaran D. Memberikan nilai akhir berdasarkan intuisi guru Jawaban: B Semoga soal-soal ini sesuai dengan kebutuhan Anda! Apakah ada peBuatlah soal kuis dari materi ini: MATERI LDKO SMP Tema: Disiplin dan Karakter SMPN 1 Pameungpeuk ________________________________________ A. Pendahuluan LDKO (Latihan Dasar Kepemimpinan Organisasi) adalah wadah penting untuk membentuk calon pemimpin muda, khususnya pengurus OSIS, agar memiliki sikap disiplin, karakter yang kuat, dan jiwa kepemimpinan. Pemimpin yang baik bukan hanya pintar berbicara, tetapi juga mampu memberi teladan melalui sikap dan perilaku sehari-hari. Pantun pembuka: Pergi ke taman memetik melati, Melati putih harum baunya. Disiplin diri sejak dini, Agar sukses di masa depan nantinya. ________________________________________ B. Pengertian Disiplin 1. Definisi Disiplin Disiplin adalah sikap patuh dan taat terhadap aturan, waktu, dan tanggung jawab, yang dilakukan dengan kesadaran diri, bukan karena paksaan. Disiplin mencakup: - Disiplin waktu (datang tepat waktu) - Disiplin aturan (menaati tata tertib) - Disiplin tanggung jawab (menyelesaikan tugas dengan baik) 2. Pentingnya Disiplin bagi Pelajar • Membentuk kebiasaan positif • Melatih tanggung jawab dan kejujuran • Menjadi dasar kesuksesan akademik dan organisasi Pantun: Jam berdentang tanda waktu, Belajar giat jangan ditunda. Disiplin itu kunci utama, Untuk meraih cita-cita. ________________________________________ C. Pengertian Karakter 1. Definisi Karakter Karakter adalah nilai-nilai moral dan sikap positif yang tertanam dalam diri seseorang dan tercermin dalam perilaku sehari-hari. Karakter bukan bawaan lahir semata, tetapi dibentuk melalui pendidikan, pembiasaan, dan keteladanan. 2. Nilai-Nilai Karakter Utama (8 Dimensi Profil Lulusan) Penguatan karakter peserta didik saat ini mengacu pada 8 Dimensi Profil Lulusan yang ditetapkan oleh Kementerian Pendidikan Dasar dan Menengah (Kemendikdasmen). Delapan dimensi ini menjadi arah pembentukan karakter siswa, termasuk dalam kegiatan LDKO dan organisasi OSIS, yaitu: 1. Keimanan dan Ketakwaan kepada Tuhan YME Tercermin dalam sikap jujur, berakhlak mulia, disiplin beribadah, serta menjunjung nilai moral dalam setiap kegiatan organisasi. 2. Kewargaan Ditunjukkan melalui kepatuhan terhadap aturan sekolah, semangat kebangsaan, cinta tanah air, dan kesediaan menjalankan hak serta kewajiban sebagai warga sekolah. 3. Penalaran Kritis Kemampuan berpikir logis, menganalisis masalah organisasi, serta mengambil keputusan secara bijak dan bertanggung jawab. 4. Kreativitas Mampu menciptakan ide-ide baru, inovatif dalam program kerja OSIS, serta berani mencari solusi atas tantangan yang dihadapi. 5. Kolaborasi Kesanggupan bekerja sama, gotong royong, menghargai perbedaan pendapat, dan membangun kekompakan antaranggota. 6. Kemandirian Sikap tidak bergantung pada orang lain, percaya diri, disiplin diri, serta mampu menyelesaikan tugas dan tanggung jawab organisasi. 7. Kesehatan Menjaga kesehatan fisik dan mental, menerapkan pola hidup bersih dan sehat, serta mampu mengelola stres dalam kegiatan organisasi. 8. Komunikasi Mampu menyampaikan pendapat dengan sopan, mendengarkan orang lain, serta berkomunikasi secara efektif dalam rapat dan kegiatan OSIS. Pantun: Pergi berlayar menuju seberang, Angin sepoi menemani bahtera. Karakter kuat delapan dimensi terkarang, Pemimpin muda siap berkarya nyata. ________________________________________ D. Keterkaitan Disiplin dan Karakter Disiplin dan karakter tidak dapat dipisahkan: - Disiplin tanpa karakter → kaku dan terpaksa - Karakter tanpa disiplin → niat baik tanpa konsistensi Pemimpin OSIS yang ideal adalah yang berkarakter kuat dan disiplin tinggi. ________________________________________ E. Penerapan Disiplin dan Karakter dalam Berorganisasi 1. Contoh Disiplin dalam Organisasi • Hadir rapat tepat waktu • Memakai seragam sesuai ketentuan • Menyelesaikan tugas sesuai deadline • Mengikuti keputusan bersama 2. Contoh Karakter dalam Organisasi • Jujur dalam laporan kegiatan dan keuangan • Tanggung jawab terhadap jabatan • Saling menghargai pendapat • Mampu bekerja sama (gotong royong) Pantun: Rapat dimulai tepat waktu, Semua hadir tanpa paksaan. Organisasi akan maju, Jika disiplin jadi kebiasaan. ________________________________________ F. Penerapan Disiplin dan Karakter dalam OSIS Sebagai organisasi siswa di sekolah, OSIS harus menjadi teladan. 1. Disiplin Pengurus OSIS • Menjadi contoh dalam menaati tata tertib sekolah • Aktif mengikuti kegiatan sekolah • Konsisten menjalankan program kerja 2. Karakter Pengurus OSIS • Kepemimpinan yang adil dan bijaksana • Berani bertanggung jawab • Peduli terhadap sesama siswa • Menjunjung tinggi nama baik sekolah Pantun: Bersama teman menanam padi, Padi tumbuh subur di sawah. OSIS disiplin, OSIS berkarakter, Sekolah maju penuh berkah. ________________________________________ G. Dasar Hukum Pelaksanaan penguatan karakter, disiplin, dan pembinaan kepemimpinan peserta didik dalam kegiatan LDKO dan OSIS berlandaskan regulasi berikut: 1. Permendikbudristek Nomor 12 Tahun 2024 tentang Kurikulum pada Pendidikan Anak Usia Dini, Pendidikan Dasar, dan Pendidikan Menengah, yang menegaskan pembentukan karakter dan kompetensi lulusan melalui pembelajaran dan kegiatan kokurikuler serta ekstrakurikuler. 2. Kebijakan Kementerian Pendidikan Dasar dan Menengah tentang Profil Lulusan (2024–sekarang), yang menetapkan 8 Dimensi Profil Lulusan sebagai acuan utama pembinaan peserta didik. 3. Permendikbud Nomor 62 Tahun 2014 tentang Kegiatan Ekstrakurikuler pada Pendidikan Dasar dan Pendidikan Menengah, yang menegaskan bahwa OSIS dan LDKO merupakan sarana pembinaan karakter, kepemimpinan, dan kepribadian peserta didik. 4. Permendiknas Nomor 39 Tahun 2008 tentang Pembinaan Kesiswaan, yang mengatur tujuan pembinaan siswa agar beriman, bertakwa, berakhlak mulia, disiplin, dan bertanggung jawab. ________________________________________ H. Penutup Disiplin dan karakter adalah fondasi utama kepemimpinan. Melalui LDKO ini, diharapkan peserta mampu menjadi pengurus OSIS yang: - Disiplin dalam sikap dan tindakan - Berkarakter Pancasila - Siap menjadi teladan bagi seluruh siswa Pantun penutup: Mentari pagi bersinar cerah, Menyinari bumi penuh harapan. Mari disiplin dan berkarakter indah, Demi masa depan gemilang. ________________________________________ “Pemimpin sejati bukan yang paling hebat memerintah, tetapi yang paling konsisten memberi contoh.”Riferimenti normativi per il settore residenziale: Art 81: Accesso alla rete viaria—>> il cancello deve essere arretrato di almeno 4,5m dal filo esterno del marciapiede Art 82: Passo carrabile—>> larghezza non inferiore a 4,5m e non superiore a 6,5m Art 83:Pendenza Rampa —>> max 16% Art 97: Superficie minima degli ambienti - cucina —>> min 5mq - studio—>> min 7mq - soggiorno—>> min 14 mq - soggiorno spazi di cottura—>> 17 -camera (1posto letto)—>> 8mq - camera (2posti letto)—>> 12mq Superficie alloggio totale —>> non inferiore a 28 mq Art 95: Altezze minime- cucina, soggiorno, camera e studio—>> min 2,70m -locali accessori—>> min 2,40 m (bagno, lavanderie) - locali di servizio—>> min 2,10m (disimpegni, riposti.) - soppalchi—>> min 2,10m - parapetti—>> non inf. a 1,1m (10 cm cordolo) (92) Art 86: Distanze - negli edifici di nuova costruzione la distanza degli edifici dal confine con proprietà di terzi — nei NAF—>> non inf. a 3 m — altri ambiti —>> non inf. a 5m Art 89: Scale (R.E. ) —alzate—>> max 12 consecutive — a chiocciola—>> consentite solo all’interno di un’unità abit. — illuminazione—>> se collegano più di due piani devono . essere areati con lucernario. Dim: 0,3 mq . per ogni piano servito (R.I.: 0,4 mq x piano) — areazione —>> non ci può essere areazione verso i vani scala . ( Lo dice anche il regolamento d’igiene ) (R.I) —>> superficie non inferiore a 1mq per piano servi. — larghezza (R.I.) —>> deve garantire la possibilità di soccorso e . trasporto di persone Art 88: Locali sotterranei —>> non possono MAI essere adibiti ad abitazione Locali seminterrati—>> possono ma devono rispettare determinati . requisiti - l’altezza media deve essere > di 2,7m Art 91: Copertura—>> istallazione di apparati tecnici non deve essere visibile . dalle pubbliche vie Art 98: Bagni —>> ambiente contenente il vaso deve essere disimpegnato . dalla cucina (R.I: disimpegnato dai locali abitabili, esclusione Secondo bagno se è a servizio esclusivo di una camera) (R.I)—>> deve essere dotato di vaso, lavabo, bidet doccia o vasca —>> il lavabo può essere ubicato nell’antibagno Art 100: Areazione —>> riscontro d’aria deve essere garantito su aperture . perpendicolari o contrapposte.(non inf. a 1\10) —>> appartamenti inf. a 60mq possono essere . monoaffaccio ( ma non esposti a nord) Art 125: Raccolta rifiuti (R.E)—>> non meno di 0,18mq per ogni abitante . virtuale —>> non meno di 5 mq —>> altezza minima 2,4m (R.I: 2 m) —>> deve avere un punto di allacciamento d’acqua Regolamento d’igiene —>> dimensione tale da poter contenere 4,5l Di rifiuti per abitante.( in ogni caso > di 2mq) —>> scarichi sifonati dall’acqua di lavaggio —>> accorgimenti che assicurino un’adeguata Difesa antimurina e antinsetti Norma UNI 10750: superficie commerciale (ciò che compriamo) , cioè la somma delle superfici coperte—>> 100% delle superfici calpestatili —>>100% delle superfici su cui poggiano . Le pareti divisorie interne non portanti —>> 50% delle pareti portanti interne perimetrali —>> 25% delle aree non abitabili Superfici scoperte—>> 25% dei balconi e delle terrazze scoperte —>> 35% dei balconi e dei terrazzi coperti (3 lati) —>> 35% dei pati e dei porticati —>> 60% delle verande —>> 15% dei giardini di appartamento —>> 10% dei giardini di ville e villini (Se un muro è al confine con un altro appartamento lo considero dalla mezzeria, se confina con uno spazio comune idem, lo considero tutto invece se da sull’esterno ) Regolamento d’igiene (su esso prevale il Re) : norme che discipilinano degli aspetti della vita quotidiana al fine di tutelare la salute dei fruitori Si occupa di : Rumori , odori , fumi, vapori. Scarichi nel sottosuolo Pulizia e decoro Malattie infettive Igenicità degli ambienti Pareti trasparenti (tenendo conto di telai e infissi)—>> deve avere un area pari a 1\8 (nazionale), 1\10 (Milano ) della superficie di pavimento Profondità di pavimento—>> non deve superare i 2,5m dalla finestra Bagno cieco solo se la superficie lorda di pavimento è inferiore ai 70mq e se è presente una sola camera da letto , oppure se è un secondo bagno (altrimenti finestra > 0,5 apribile). Superficie illuminante—>> superficie totale dell’apertura meno - superficie finale non utile (C): 60 cm - superficie superiore non utile (A) A= va considerato per intero se non ci sono aggetti o se questi sono inferiori a 150 cm. Al contrario ne considero solo un terzo. Es: con aggetto, b+ 1\3a . Se il rapporto illuminante è rispettato la profondità del locale non può essere più di 2,5 volte l’altezza del voltino . Se non è rispettato (inferiore a 1\8) allora deve essere 3,5 volte Alloggi devono essere dotati— per 1\2 perone—>> 1 spazio cottura,1 servizio igienico , 1 ripostiglio — per 3\4 persone—>> 1 cucina indipendente, 1 servizio igienico , 1 ripostiglio — per 4\5 persone —>> 1 cucina indipendente, 2 servizi igienici, 1 ripostiglio (per il secondo servizio è richiesta una superficie minima di 2mq e un lato minimo di 1,2m) Dotazione dei servizi: Cucina—>> pavimenti e pareti con superficie Di materiale impermeabile, liscio, lavabile,resist. —>> soffitto materiale traspirante —>> cappa collegata a ogni punto di cottura (Vedi bagno su) Prevenzione incendi : definisce —dimensionamenti—accessi all’area (locali di intrattenimento e di pubblico Spettacolo —>> larghezza 3,5 —>> h libera 4m —>> raggio di svolta 13m —>> pendenza non sup al 10% —>> resist al carico almeno 20t —profondità locali —>> i locali al chiuso non possono Essere ubicati oltre il secondo piano Interrato (non oltre i 10m) . Questi se Sono tra i 7,5 e i 10 m devono essere Protetti da un’impianto sprinkler e Essere dotati di uscite sicure. — carichi d’incendio — comunicazione (locali di intrattenimento e di pubb. Spettacolo —>> locali possono comunicare con altre Attività purché dotate di filtri a prova di Fumo e di porte REI (ameno 30) (queste Non vanno cont nel comp. delle vie d’uscit) — compartimentazioni — autorimesse — comportamento al fuocoCrea un quiz con le seguenti domande. Inserisci anche la spiegazione. Domande Vero/Falso: 1. Vero o Falso: Se moltiplichiamo entrambi i membri di una disequazione per un numero negativo, il segno dell'ineguaglianza cambia. o Risposta: Vero o Spiegazione: Quando moltiplichiamo o dividiamo entrambi i membri di una disequazione per un numero negativo, il segno dell'ineguaglianza si inverte. 2. Vero o Falso: Una disequazione può avere solo una soluzione. o Risposta: Falso o Spiegazione: Una disequazione può avere zero, una o infinite soluzioni, a seconda dei valori coinvolti. 3. Vero o Falso: Se sommiamo o sottraiamo la stessa quantità da entrambi i membri di una disequazione, la soluzione rimane invariata. o Risposta: Vero o Spiegazione: Aggiungere o sottrarre la stessa quantità da entrambi i membri di una disequazione non cambia la relazione tra le soluzioni. 4. Vero o Falso: Se abbiamo una disequazione del tipo 2x>102x>10, la soluzione è x<5x<5. o Risposta: Vero o Spiegazione: Dividendo entrambi i membri per 22, otteniamo x>5/2x>5/2, che può essere semplificato a x>2.5x>2.5 o x>5/2x>5/2. 5. Vero o Falso: Una disequazione può avere solo numeri interi come soluzioni. o Risposta: Falso o Spiegazione: Le soluzioni di una disequazione possono essere numeri razionali o reali, non solo numeri interi. 6. Vero o Falso: Una disequazione del tipo 3x−2<53x−2<5 ha x>7/3x>7/3 come soluzione. o Risposta: Falso o Spiegazione: La soluzione corretta è x<7/3x<7/3 poiché 3x−23x−2 deve essere minore di 55, non maggiore. 7. Vero o Falso: Una disequazione del tipo 4x+7≥3x+54x+7≥3x+5 ha una soluzione unica. o Risposta: Vero o Spiegazione: Sottraendo 3x3x da entrambi i lati otteniamo x+7≥5x+7≥5, che semplificato diventa x≥−2x≥−2, quindi ha una soluzione unica. 8. Vero o Falso: Una disequazione quadratica è un tipo di disequazione di primo grado. o Risposta: Falso o Spiegazione: Una disequazione quadratica coinvolge il quadrato di una variabile e può essere di secondo grado o superiore, mentre una disequazione di primo grado coinvolge solo variabili elevate alla prima potenza. 9. Vero o Falso: Una disequazione del tipo 2(x−3)<82(x−3)<8 può essere risolta dividendo entrambi i membri per 22. o Risposta: Vero o Spiegazione: Dividendo entrambi i membri otteniamo x−3<4x−3<4, che può essere semplificato a x<7x<7 dopo l'aggiunta di 33 ad entrambi i membri. 10. Vero o Falso: Se abbiamo una disequazione del tipo x≤4x≤4 e x≥3x≥3, allora la soluzione è x=4x=4. o Risposta: Falso o Spiegazione: La soluzione è 3≤x≤43≤x≤4, il che significa che xx può essere qualsiasi numero tra 33 e 44, inclusi tutti i valori decimali in questo intervallo. Domande a Risposta Multipla: 11. Qual è la soluzione della disequazione 2x+5>112x+5>11? a) x<3x<3 b) x>3x>3 c) x<8x<8 d) x>8x>8 o Risposta: b) x>3x>3 o Spiegazione: Sottraendo 55 da entrambi i lati otteniamo 2x>62x>6, quindi x>3x>3. 12. Quale delle seguenti è una soluzione della disequazione 3x−1≤83x−1≤8? a) x=3x=3 b) x=1x=1 c) x=0x=0 d) x=4x=4 o Risposta: d) x=4x=4 o Spiegazione: Aggiungendo 11 ad entrambi i lati otteniamo 3x≤93x≤9, quindi x≤3x≤3. 13. Quale delle seguenti disequazioni è equivalente a 2(x+1)>62(x+1)>6? a) 2x>62x>6 b) 2x+2>62x+2>6 c) x+1>3x+1>3 d) x>2x>2 o Risposta: c) x+1>3x+1>3 o Spiegazione: Distribuendo 22 otteniamo 2x+2>62x+2>6, quindi x+1>3x+1>3. 14. Qual è la soluzione della disequazione 5x−4<3x+75x−4<3x+7? a) x<11x<11 b) x>11x>11 c) x<−11x<−11 d) x>−11x>−11 o Risposta: d) x>−11x>−11 o Spiegazione: Sottraendo 3x3x da entrambi i lati otteniamo 2x−4<72x−4<7, quindi 2x<112x<11 e infine x>−11x>−11. ……. 15 Qual è la soluzione della disequazione 2x+3≥5x−12x+3≥5x−1? a) x≤−1x≤−1 b) x≥−1x≥−1 c) x<2x<2 d) x>2x>2 o Risposta: c) x<2x<2 o Spiegazione: Sottraendo 5x5x da entrambi i lati otteniamo −3x+3≥−1−3x+3≥−1, quindi −3x≥−4−3x≥−4. Dividendo entrambi i lati per −3−3, ricordando di invertire il segno, otteniamo x<2x<2. 16 Quale delle seguenti è una soluzione della disequazione 4x−2≤2x+64x−2≤2x+6? a) x≤−2x≤−2 b) x≥−2x≥−2 c) x<2x<2 d) x>2x>2 o Risposta: b) x≥−2x≥−2 o Spiegazione: Sottraendo 2x2x da entrambi i lati otteniamo 2x−2≤62x−2≤6, quindi 2x≤82x≤8 e infine x≥−2x≥−2. 17 Quale delle seguenti è la soluzione della disequazione 3(x−2)>93(x−2)>9? a) x>3x>3 b) x>5x>5 c) x<3x<3 d) x<5x<5 o Risposta: b) x>5x>5 o Spiegazione: Dividendo entrambi i lati per 33, otteniamo x−2>3x−2>3, quindi x>5x>5. 18 Qual è la soluzione della disequazione 2x+4≤102x+4≤10? a) x≤2x≤2 b) x≥2x≥2 c) x<2x<2 d) x>2x>2 o Risposta: a) x≤2x≤2 o Spiegazione: Sottraendo 44 da entrambi i lati otteniamo 2x≤62x≤6, quindi x≤3x≤3. Tuttavia, dovremmo tenere conto che 22 è positivo, quindi la soluzione è x≤2x≤2. 19 Quale delle seguenti disequazioni è equivalente a 2x≤82x≤8? a) x≥4x≥4 b) x≤4x≤4 c) x>4x>4 d) x<4x<4 a. Risposta: b) x≤4x≤4 b. Spiegazione: Dividendo entrambi i lati per 22, otteniamo x≤4x≤4. 20 Quale delle seguenti è una soluzione della disequazione 5(x−3)>105(x−3)>10? a) x<−1x<−1 b) x>−1x>−1 c) x>5x>5 d) x<5x<5 a. Risposta: c) x>5x>5 b. Spiegazione: Dividendo entrambi i lati per 55, otteniamo x−3>2x−3>2, quindi x>5x>5.