When the skin comes in contact with an irritant, receptors in the skin send signals to the spinal cord. The signal is then sent to the brain for processing, and the individual begins to scratch the affected area.

Which two systems are most likely interacting when a person experiences itching caused by a skin irritant?

During the cell cycle, proteins called cyclins bind to enzymes that send signals for the cell to progress through stages of cell replication. At the end of this cycle, the cyclins degrade to prevent further signaling for the cell to divide.

Uncontrolled production of cyclins will most likely result in — 

Farmers spray pesticides on their plants to protect the plants from being eaten by insects. Some individual insects have a genetic mutation that makes them resistant to the toxins in the pesticides.

Which statement best describes how only a few resistant individuals resulted in the pesticide becoming ineffective?

Which property is shared by the cells of all living things?

Which graphic organizer best compares the energy inputs and outputs of cellular respiration and photosynthesis?

Overfishing is causing the decline of fish populations, such as Eastern Atlantic bluefin tuna in the Mediterranean. Eastern Atlantic bluefin tuna are caught faster than they can reproduce.

Which statement describes the most likely effect that overfishing will have on this ecosystem?

Which statements best compare the function of an ATP molecule to a DNA molecule?

Students created note cards comparing characteristics of eukaryotic and prokaryotic cells. Which set of note cards most accurately compares these cells?

The Mexican long-nosed bat roosts in Big Bend National Park in West Texas. The bat feeds on nectar and pollen and hovers while it feeds. Additionally, its tongue can extend up to eight centimeters.

The features of Mexican long-nosed bats are evidence of natural selection because the features are adaptations that —

Which statement describes the process of osmosis in an animal cell?

Sand dunes along the coast are formed of bare sand. Eventually, grasses take root on the dunes. Over time, larger plants such as shrubs and trees are able to grow at the edge of the sand dune ecosystem.

This gradual change in plant communities of a sand dune ecosystem can result in —

A researcher determines an organism to be eukaryotic, unicellular, and autotrophic. In which taxonomic group should this organism be classified?

For an enzyme to be able to catalyze a reaction, the active site must —

Snowshoe hares can be found living in the Rocky Mountains of New Mexico. During the summer months, when there is no snow on the ground, the snowshoe hare’s coat color is typically brown. During the winter months, when the mountains are covered in snow, the snowshoe hare’s coat is typically white.

Which statement describes the genetic basis for the seasonal changes in coat color?

In an experiment, two plants are grown together for a time and then separated. Plant 2 is a parasite of Plant 1.

Which graph best predicts the growth of Plant 1 and Plant 2 during the experiment?

When multiple transitional fossils are found in many rock layers, they provide evidence of —

Environmental factors typically activate genes in a cell by causing the cell to —

A genetic cross involving two unlinked genes is represented.

AaGG x aaGg

Which genotype is NOT possible in the offspring produced by the cross?

A farmer is struggling to control the population of a certain insect on his farm.  After researching population control techniques, he discovers that a particular bird is a predator of this insect. The farmer purchases a number of these birds and releases them onto his farm.

How might the farmer’s action most likely have a negative impact on the ecosystem?

Which statement is an example of how carbon moves through a food chain as part of the carbon cycle?

Which table correctly identifies how the plasma membrane contributes to the maintenance of cellular homeostasis?

In Texas Longhorn cattle, coat coloration is an inherited trait. What is the genetic basis of coat-color variation in Texas Longhorn cattle?

When a new mutation occurs in a somatic cell of a sexually reproducing organism, what percentage of the individual’s offspring are likely to inherit the mutation?

Researchers have observed striped hyenas and gray wolves hunting together in certain areas. One hypothesis suggests that changing hunting behavior aids both species in obtaining better and more resources. In this hypothesis the hyenas benefit because the wolves chase and take down large animals, such as goats, that the hyenas usually cannot catch alone. The wolves benefit from hyenas using their jaw strength to crack open large bones of prey to access additional nutrients from bone marrow.

Which table best identifies the ecological relationships among the gray wolf, hyena, and goats?

The giant octopus lays 20,000 to 100,000 fertilized eggs. After hatching, most octopuses become prey to larger marine organisms, and less than 5% will reach adulthood to reproduce.

One benefit of the giant octopus laying many eggs is to —

Which statement best describes how bacteria recycle matter in an ecosystem?

An illness caused by a certain virus includes fever, rash, joint pain, red eyes, and headache. The virus is transmitted to people by infected mosquitoes. Symptoms quickly occur within three to twelve days after contracting the virus. There is no vaccine for this virus.

Which description best explains the reproductive cycle of this virus?

Which statement best describes an interaction between the muscular system and the respiratory system?

Two scientists want to compare their research of fireflies. Which information must the two scientists provide to each other to determine if they studied the same type of fireflies?