Why are phytoplankton essential to aquatic life zones?
select one:
a. filter pollution from water
b. provide basis of food chains
c. moderate water temperature
d. produce chemicals that can be used against predators

Phytoplanktons are also called microalgae. They are the foundation of the aquatic food web and the primary producers. They feed everything from microscopic to multi-ton whales. Thus, the answer to the question above is letter B. Provide basis of food chains.