Question

Pesticides, such as DDT, often have harmful effects on aquatic ecosystems. One harmful effect would be that these pesticides

A) cause fish to become sterile and unable to lay eggs.

B) cause algae and plants to overgrow and pollute the water when they die.

C) accumulate in animals and build up in toxic concentrations as they pass through the food chain.

D) eliminate most of the algae and plants in the food chain, causing animals to starve, at higher levels of the food chain.

Answer 1

The answer is C. When a pesticide like DDT enters the ecosystem, the concentration of the DDT exponentially grows as you go down the food chain. For example if DDT was in the algae, the fish eating the algae would consume large amounts of of the DDT that was in the algae, therefore having more DDT. Anything that would eat the fish would consume the DDT that the fish ate from eating the algae and would have even higher concentration of DDT. Eventually the top predator will consume the highest amount of DDT.