Over time, the mushrooms that grow in a certain forest have been overharvested by humans. As a result, the number of mushrooms in the area has decreased dramatically.

How will this most likely affect the environment?

Fewer forest trees will become infected with harmful Dutch elm disease.
Carbon dioxide levels will decrease since mushrooms release it when they make food.
The amount of oxygen released into the air will decline and the forest plant life will eventually die off.
Dead plant and animal waste will build up on the forest floor, attracting pesky insects and scavengers.