Ecosystem Interactions – Multiple Choice 1.C – Decomposers recycle matter, changing it from dead organisms and waste material to nutrients that are available to producers. 2.A - Commensalism, in which one species benefits and the other is unaffected, is not represented in this situation. 3.D – The highest tropic level is generally the smallest. Since energy is lost as it is transferred from one trophic level to the next higher level.

A.Any food chain through the ecosystem from sun to humans is acceptable. Example: phytoplankton, mussels, crabs, humans B.When consuming a seaweed salad, a person is acting a primary consumer. When consuming striped bass the same person is acting as a tertiary or quaternary consumer. Ecosystem Interactions – Constructed Response

C.Decomposers are missing from the food web. They return nutrients to the water, allowing producers (phytoplankton and seaweed) to grow. Because the entire ecosystem depends on producers, decomposers play a crucial role in the ecosystem. Ecosystem Interactions – Constructed Response