Suppose the water of a lake is contaminated by a pesticide. Arrange the following in the increasing order of accumulated concentration of the pesticide in the lake ecosystem.

1.Water

2.Zooplankton

3.Phytoplankton

4.Fish

5.Bird

A5, 4, 3, 2, 1

B1, 2, 3, 4, 5

C1, 3, 2, 4, 5 ✓ Correct

D3, 2, 4, 5, 1

Correct answer: (C) 1, 3, 2, 4, 5

Explanation

Pesticide concentration climbs up the food chain, lowest in water and highest in the top bird.

Water holds the most dilute trace of the pesticide.

Phytoplankton absorb the pesticide from water and hold slightly more.

Zooplankton eat many phytoplankton and store a higher dose.

Fish feed on large numbers of zooplankton, concentrating it further.

The bird at the top eats many fish and carries the highest load.

This rising build-up along the chain is called biomagnification.

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