Final answer:
A pollutant that degrades or breaks down slowly in the environment is most likely to bioaccumulate in a food web.
Step-by-step explanation:
A pollutant with characteristics that make it likely to bioaccumulate in a food web is one that degrades or breaks down slowly in the environment. This is because a pollutant that breaks down slowly will persist in the environment, allowing it to build up in the bodies of organisms over time. Examples of such pollutants are PCBs (polychlorinated biphenyls) and mercury, which are known to accumulate in the bodies of fish and other animals.
Learn more about Bioaccumulation