Biomagnification of DDT in food chains

Steps:

• DDT is a persistent pesticide that bioaccumulates in fatty tissues of organisms.
• It biomagnifies, increasing in concentration at each trophic level.
• Aquatic plants absorb minimal DDT directly.
• Concentrations peak in top predators consuming contaminated prey.

Why D is correct:

• Biomagnification (increase in toxin levels up the food chain) results in the highest DDT concentrations in apex predators like fish-eating birds, causing severe reproductive harm per ecological laws of pollutant transfer.

Why the others are wrong:

• A: Aquatic plants are primary producers with the lowest DDT exposure and no bioaccumulation.
• B: Carnivorous fish accumulate DDT but at lower levels than birds that eat them.
• C: Herbivorous fish have moderate exposure from plants, less than carnivores.

Final answer: D