Which term is the increasing concentration of a harmful substance in organisms at higher trophic levels?

• A. Biological magnification
• B. Biodiversity
• C. Acid rain
• D. Genetic drift

Answer: (A)

Biomagnification is the increasing concentration of a harmful substance as you move up the food chain. When a predator eats prey, it ingests the toxins contained in that prey. If the chemical is persistent and fat-soluble, it isn’t easily broken down or excreted, so it accumulates in the predator’s body. Because a predator consumes many prey, the toxin becomes more concentrated at each higher trophic level. This is why top consumers often carry the highest levels of pollutants like DDT or methylmercury. The other terms don’t describe this pattern: biodiversity is about variety of life, acid rain refers to environmental acid deposition, and genetic drift is random change in allele frequencies over time.