Question

The second trophic level in a lake is

• A. Phytoplankton
• B. Zooplankton
• C. Benthos
• D. Fishes

Answer 1

The correct option is B

Zooplankton

The correct option is B.

Explanation of the correct option:

1. In a lake ecology, zooplanktons are at the second trophic level.
2. The principal producers of lake ecosystems are phytoplanktons.
3. Phytoplanktons provide food for zooplankton (primary consumers).
4. Phytoplanktons are tiny algae that live in the upper reaches of lakes.
5. They must be exposed to sunshine in order to flourish.
6. Zooplanktons may be found in both freshwater and marine habitats.
7. Zooplanktons are heterotrophic planktons, which include cnidarians, crustaceans, and mollusks.

Explanation of the incorrect options:

Option A:

1. Phytoplankton is a tiny marine alga that plays an important role in the seas.
2. They feed a variety of water species, including whales, snails, and jellyfish.

Option C:

1. Benthos is the aquatic vegetation found in freshwater bodies.
2. Benthos are at the bottom of the food chain.

Option D:

1. Fishes consume phytoplankton and zooplankton.
2. Fishes are secondary consumers and are classified as belonging to the third trophic level.

Final answer: The second trophic level in a lake is zooplankton.