Question

Which is the correct food chain?
A) Phytoplankton → Fishes → Zooplankton
B) Zooplankton → Phytoplankton → Fishes
C) Phytoplankton → Zooplankton → Fishes
D) Fishes → Zooplankton → Phytoplankton

Answer 1

Hint: In an ecosystem, the food chain is characterized as a single food pathway from one trophic level to the next higher trophic level, or connecting a producer with a different level of consumer.

Complete answer
To answer this question we have to know about the food chain. The base of life in the marine environment is phytoplankton (single-celled organisms floating in water). To transform energy from sunlight into chemical energy (to prepare food), they use photosynthesis. Both small and large animals in marine environments can be consumers of phytoplankton. When zooplanktons eat phytoplankton, some of this food travels directly through the food chain and in turn is eaten by larger animals such as fish, whales, squid, shellfish and birds. This cycle occurs two more times, with tertiary consumers consuming secondary consumers and eventually apex predators killing tertiary consumers, the animals at the top of the food chain. Only plants that are herbivores may be consumed by consumers, or they may eat smaller animals that are carnivores, or they may eat both that are omnivorous.

 Food produced by phytoplankton can also enter another pathway dominated by bacteria through chemosynthesis.

Hence, phytoplankton is a component of the pond ecosystem present at the first trophic level. Zooplankton occupies the second trophic level. Small fishes occupy the third trophic level in a food chain.

Thus, the correct option is ‘C’. Phytoplankton → Zooplankton → Fishes.

Note:The foundation of almost all food chains on Earth is photosynthesis. It's also true of marine food chains. Organisms break down chemicals in chemosynthesis to make energy for food. Marine decomposers break down dead organisms just like on land. Nutrients are released from them.