Phytoplankton
Fish
Zooplankton
Frog
The Correct option is B: Fish.
In an aquatic ecosystem, fish can consume phytoplankton and other producers. In this context, fish act as primary consumers or herbivores in the grazing food chain. Some larger fish may also prey on smaller fish. Phytoplankton are always producers, while zooplankton are always primary consumers. Frogs function as secondary consumers, feeding on primary consumers such as insects.
Thus, the correct answer is option B.
Assertion (A): Food web is a network of several food chains operating in an ecosystem.
Reason (R): Food web decreases the stability of an ecosystem.
Consider the following food chain: Grass → Grasshopper → Frog → Snake → Eagle If the amount of energy available at third trophic level is 50 kJ, the available energy at the producer level was:
We do not clean natural ponds or lakes, whereas an aquarium or a swimming pool needs to be cleaned regularly. Why?