Identify the correct sequence of trophic levels in a food-chain.

(A) Man
(B) Phytoplankton
(C) Fishes
(D) Zooplankton

Choose the correct answer from the options given below:

(B), (D), (C), (A)

The correct answer is Option (3) → (B), (D), (C), (A) 

(B) Phytoplankton

(D) Zooplankton

(C) Fishes

(A) Man

To match the trophic levels in an ecosystem with the correct examples from the given lists, we need to understand the flow of energy and the position of each organism in the food chain.

Trophic Levels:

First trophic level: Producers (e.g., plants, phytoplankton) that make their own food via photosynthesis.

Second trophic level: Primary consumers (Zooplankton) that feed on producers.

Third trophic level: Secondary consumers (fishes) that feed on primary consumers.

Fourth trophic level: Tertiary consumers (man) that feed on secondary consumers.

So,

The correct sequence of organisms in an ecosystem from lower to higher trophic order is:

• Phytoplankton (B) are primary producers (autotrophs) at the base of the food chain.
• Zooplankton (D) are primary consumers (herbivores) that feed on phytoplankton.
• Fish (C) are secondary consumers (carnivores/omnivores) that feed on zooplankton.
• Man (A) is a tertiary consumer (top carnivore/omnivore) that may feed on fish.