Pesticides were sprayed in a lake to control mosquitoes. The food chain in this lake comprises phytoplankton, small fish, hawk, and large fish. Arrange these organisms into a correct food chain and state which organism will have the maximum concentration of pesticides in its body. Give a reason for your answer.

Step-by-step solution

1. Step 1: Arrange the organisms in sequential trophic levels: Phytoplankton (producer) $\to$ Small fish (primary consumer) $\to$ Large fish (secondary consumer) $\to$ Hawk (tertiary consumer).
2. Step 2: Identify that pesticides are non-biodegradable chemicals that get absorbed by producers and cannot be broken down or excreted by organisms.
3. Step 3: Apply the concept of biological magnification, which states that non-biodegradable chemicals accumulate progressively at each trophic level. Since the hawk occupies the highest trophic level, it accumulates the highest concentration of pesticides.

Concept tested: Biological magnification in food chains

Published 24 August 2026 · How this solution was prepared and checked

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