Consider the model of the food chain. imagine a local farm has dumped excess pesticides in the pond used for irrigation. this will impact the food chain in the pond in all but one way. that is a) the fish populations will drop. b) the algae will grow thicker in the pond. c) the algae growing in the pond will die out. d) fishing will not produce much positive results.

C

Explanation:

The deposition of pesticides in the bond with result to increase in bacteria that breakdown the chemicals for energy. This provides ‘food’ for bacteriophages and then food for algae that will thrive in the pond. They take up oxygen from the pond and make the waters anoxic. The fish will, therefore, be smothered and their numbers will reduce in the pond.

the algae will grow thicker in the pond.

Explanation:

A pond contains a vibrant ecosystem comprising of algae and fishes as the most common biotic components.

When a pesticide is introduced into this pond, the biotic components are adversely affected by the dangerous chemical and they quickly begin to die of chemical poisoning. Both the algae and the fishes alike will die of this chemical poisoning.

Hence the algae does not grow thicker because it is poisoned by the harsh chemical introduced into the ecosystem.