Which statement defines biomagnification?

• A. Toxins become more concentrated as they move up the food chain.
• B. Toxins accumulate in a single organism only.
• C. Toxins are diluted as they move through ecosystems.
• D. Toxins are eliminated quickly from the environment.

Answer: (A)

Biomagnification is the process by which certain persistent toxins become more concentrated as they move from prey to predator up the food chain. When a predator eats many contaminated organisms, the toxin isn’t easily broken down or excreted, so it accumulates in the predator’s body. Over successive steps up the chain, this buildup gets larger, so top predators end up with the highest concentrations. A classic example is DDT entering aquatic food webs and becoming increasingly concentrated in birds of prey, contributing to problems like eggshell thinning. This differs from simple bioaccumulation in a single organism (where the toxin builds up inside one organism) and from dilution or rapid environmental elimination, which would reduce concentrations rather than increase them as you move up the chain.