Which of the following results in bioaccumulation and contamination of food chains?

Pesticides build up in tissues and become concentrated along food chains through bioaccumulation.

Polychlorinated biphenyls persist too, but the classic food-chain example is pesticides like DDT.

PAN is an air pollutant that irritates tissue rather than accumulating in food chains.

Grouping all three overstates the case, since PAN does not bioaccumulate.

Fat-soluble pesticides magnify at each higher trophic level, a process called biomagnification.

Top predators therefore carry the heaviest pesticide loads.