A freshwater ecosystem has various food webs. One of these food webs is shown below. Which organisms transfer the most energy within the food web?

The table below lists the preferred diet of several types of birds. Based on this information, which two types of birds do not compete for food resources?

Some students examined two samples of pond water with a hand lens over three days. Each day they compared what they saw with pictures of samples their teacher had labeled. Their observations are listed below. Based on their observations, the students concluded that mosquitoes undergo complete metamorphosis while dragonflies undergo incomplete metamorphosis. Which of these explains why the students’ conclusion is correct?

A student observes the following activities while walking in a park. Which of these living organisms was interacting with another living organism in the environment?

The nesting habits of four types of birds are described in the table below. If all the dead branches and dying trees in a wooded area are removed, which bird’s nesting habit would be most affected?

A food web for some organisms in an African rain forest is shown below. Which organisms in this food web eat only consumers?

Some animals, such as lions, have pointed teeth, while other animals, such as cattle, have flat teeth. The difference in the shape of these animals’ teeth is most closely related to —

A group of students made the observations listed below about the size, shape, and appearance of their hands. Which of the students’ observations describe inherited traits?

A partial food web of a pond ecosystem is shown below. Which type of organism is missing from this food web?

For a science assignment a student was asked to observe some organisms and then make a table to classify the organisms’ traits as inherited or learned. The student’s table is shown below.

The shells of sea turtles are flatter than the shells of land turtles. Sea turtles are also different from land turtles because sea turtles cannot pull their head or limbs into their shell to protect themselves from predators. Instead, the head, shell shape, and flippers of sea turtles help them escape from predators mainly by allowing them to —

Many types of grazing animals live in Africa. The pictures show two of these animals that have about the same mass and height at the shoulder. Based on observations of the pictures of these animals, which statement describes an advantage that only one of these animals has in obtaining food?"

A farmer is reading a nature guide to learn how to make changes to a pond so that it will attract and support wildlife. The guide gives the suggestions listed below. Which suggestion involves interactions between two groups of living organisms?

A partial forest food web is shown. In this food web, energy is transferred directly between —

Data for four animal populations in a wooded area were collected before and after a shopping mall was constructed near the area. The graph shows changes in the populations. Which animal’s food sources most likely increased after the mall opened?

Many desert animals depend on the prickly pear cactus. What role does the prickly pear cactus play in a desert food web?

The table gives information about four types of fish. These fish all have mouth structures that allow them to eat different types of food. Which of these fish has mouth structures that allow it to eat algae by taking large bites of the hard coral on which the algae grows?

Green anole lizards are bright-green reptiles native to the southeastern United States and the Caribbean islands. They can be kept in terrariums to study their behavior and how they interact with their environment.Which observation describes this anole lizard interacting with the living elements in its environment?

Big Bend National Park is located in the part of the Chihuahuan Desert that is in southwestern Texas. The table below lists some of the types of animals that live in Big Bend and what they eat. Based on the information in the table, which of the following food chains shows one way energy flows in the Big Bend ecosystem?

Many gardeners use red worms like the ones shown in the photograph to turn vegetable and fruit scraps into topsoil for plants. The gardeners build a worm farm in a large container lined with old newspapers and filled with moist garden soil. The worms eat about half their body weight daily and produce waste that can be used as plant fertilizer. The container for a worm farm needs to have a lid, but the lid must be left partially open because worms require which of the following in order to survive?