Question

which sentence best explains bioaccumulation?

a. materials containing metal are toxic to organisms that live in them.

b. an increased growth in microorganisms results in oxygen depletion.

c. there are millions of cholera cases per year due to contaminated water.

d. the mercury contained in fish builds up in animals that eat the fish.

Explanation:

Bioaccumulation is the process where substances (like toxins) accumulate in an organism's body over time, and can also build up in organisms higher up the food chain when they consume organisms with the accumulated substance. Option D describes mercury (a toxin) in fish building up in animals that eat those fish, which matches bioaccumulation. Option A is about metal toxicity, B about microbial growth and oxygen depletion, C about cholera from contaminated water—none relate to bioaccumulation.

Answer:

D. The mercury contained in fish builds up in animals that eat the fish.