Final answer:
Bio-accumulation refers to the gradual accumulation of toxins in an individual organism, while biomagnification occurs when toxins become increasingly concentrated as they move up the food chain.
Step-by-step explanation:
Bio-accumulation and biomagnification are both processes by which toxins and pollutants are concentrated in organisms in an ecosystem, but they occur at different levels of the food chain.
Bio-accumulation refers to the gradual accumulation of toxins in an individual organism over its lifetime. This can happen when an organism consumes food or water that contains low levels of toxins, but accumulates them over time. For example, if a fish lives in a polluted river, it may accumulate toxins in its body over time.
Biomagnification occurs when toxins become increasingly concentrated as they move up the food chain. This happens because organisms at higher trophic levels consume larger amounts of prey that contain toxins. For example, if a small fish has consumed many small insects that contain toxins, and then a larger fish consumes many of those small fish, the toxin concentrations will be magnified in the larger fish.