Final answer:
Biomagnification accurately describes the process where the concentration of toxic substances like pesticides increases at each higher trophic level in the food chain, which has been exemplified by substances like DDT and PCBs.
Step-by-step explanation:
Biomagnification is true to mean that pesticides are magnified as they move up the food chain. This process is the increasing concentration of persistent toxic substances such as pesticides and heavy metals in organisms at each successive trophic level. One of the most well-known examples of biomagnification involves the pesticide dichlorodiphenyltrichloroethane (DDT), which was highlighted in Rachel Carson's book Silent Spring. DDT usage was outlawed in the United States during the 1970s due to its impact on apex consumers like birds, causing thinning of their eggshells. Another substance that has shown effects of biomagnification is polychlorinated biphenyl (PCB), which was banned in 1979. Additionally, the biomagnification of heavy metals, such as mercury, is a concern, especially in the consumption of certain seafoods.