Final answer:
Zooplankton are heterotrophic organisms that are a part of the plankton community in aquatic ecosystems, feeding on phytoplankton and serving as a crucial food source for nekton.
Step-by-step explanation:
Zooplankton are a type of plankton, which are small aquatic organisms that drift in the water column. Unlike their counterpart, phytoplankton, zooplankton are not capable of photosynthesis, and instead, they are heterotrophic, meaning they feed on other small organisms, such as phytoplankton or other zooplankton. Zooplankton can include a variety of life forms, such as protozoans, tiny crustaceans, and the eggs and larval stages of larger animals. Often found in the photic zone of aquatic environments, they play a crucial role in aquatic food webs and are a primary food source for other aquatic organisms like fish and shrimp, classified as nekton.