Which of these is an example of bioremediation?
a - the mercury contained in fish builds up in animals that eat the fish.
b - bacteria are introduced to break down hydrocarbons in an oil spill.
c - materials containing metal are toxic to organisms that live in them.
d - an increased growth in microorganisms results in oxygen depletion

B. Bacteria are introduced to break down hydrocarbons in an oil spill.

B - Bacteria are introduced to break down hydrocarbons in an oil spill.

Explanation:

Bioremediation is a process of treatment of used cultures, medium, soil and water with microorganisms, and plants which absorbs the pollutants from these sources and removes the contamination.

B - Bacteria are introduced to break down hydrocarbons in an oil spill. is the correct option this is because of the fact that the bacteria will break down the components of the oil that includes the hydrocarbons. This will disturb the structure of the oil and will make it unreactive and harmless to the aquatic species.