Answer:
A) Phytoplankton
Explanation:
All organisms need energy which they derive by naturally feeding on one another in a series of chain called FOOD CHAIN. The food chain can form a more complex interrelated series called FOOD WEB. All food chains and webs starts with a set of unique organisms called PRODUCERS.
Producers are autotophs that produce their own food via the process of photosynthesis. They are the only set of organisms that have the ability to tap the energy from the sun, which then flows in the food chain as organisms feed on one another.
Phytoplanktons are aquatic producers, hence, they photosynthesize in water. The food chain will be immediately affected if the phytoplanktons (producers) are removed from the food web because there will be no organism to start the energy flow.
