Which statement describes the role of decomposers in a food web?

• A. Decomposers are not necessary in a food web.

• B. Decomposers break down matter so plants can use it.

• C. Decomposers create energy by producing their own food.

• D. Decomposers store matter and energy until it is needed in an ecosystem.

Producers and consumers are both pictured in a diagram of a food web. Which statement best describes how they differ from one another?

• A. Consumers produce all the energy they need.

• B. Consumers eat only animals, and producers eat only plants.

• C. Producers eat living organisms, and consumers eat organisms that have died.

• D. Consumers obtain energy by eating food, and producers obtain energy from sunlight.

What is the primary role of decomposers in a food web?

• to control the population of producers and consumers

• to compete with producers for energy and other resources

• to provide a source of energy for the producers in the ecosystem

• to recycle energy and materials from dead producers and consumers

Different grasses are observed in a microhabitat in a schoolyard. Why is grass an essential part of a healthy ecosystem?

• It is a producer that is a necessary part of the diet of most consumers.

• It is a consumer that feeds off other organisms living in the area.

• It is a decomposer that converts matter into a form that other organisms can use.

• It makes up the last level of a food web, helping recycle carbon in the habitat.

A student is identifying food chains in a diagram of a food web. Which of these organisms might be a consumer?

• A. frog

• B. water lily

• C. redwood tree

• D. athlete’s foot fungus

According to the food web, which organism is a producer in the mangrove swamp?

• mold

• prawn

• pelican

• phytoplankton

If there was a decrease in the beetle population, how might the food chain be affected?

• The owl population would increase.

• The population of green plants would decrease.

• The toad and snake populations would increase.

• The toad populations would decrease.

One benefit of using a terrarium to model the interactions of plants and animals in a forest ecosystem is:

• It allows for controlled observation of interactions.

• It exactly replicates all conditions of a real forest.

• It eliminates the need for any real organisms.

• It prevents all environmental changes.

One limitation of using a terrarium to model the interactions of plants and animals in a forest ecosystem is that:

• it cannot replicate all environmental factors found in a real forest

• it allows for unlimited space for organisms to move

• it includes all species present in a forest

• it provides natural weather patterns

The carbon cycle involves the movement of carbon among which of the following?

• Only plants and animals

• The atmosphere, plants, animals, and the earth

• Only the atmosphere and oceans

• Only rocks and soil