Final answer:
Humans play a role in biomagnification by consuming organisms that have accumulated toxic substances, which become more concentrated as they move up the food chain.
Step-by-step explanation:
Biomagnification is the increasing concentration of persistent, toxic substances in organisms at each successive trophic level. Humans play a role in biomagnification when they consume organisms that have accumulated these substances. For example, when humans consume predatory fish species like swordfish, they are at a higher risk of being exposed to higher levels of toxins, such as mercury, compared to smaller species like anchovies. This is because the toxins become more concentrated as they move up the food chain.