In a Long-Term Experiment at Hubbard Brook in New Hampshire

In a long-term experiment at Hubbard Brook in New Hampshire, scientists compared an undisturbed valley with a valley that had all the plants removed. What did they discover?

A) Plants produce an important amount of oxygen in an ecosystem.
B) Forests play a minor role in maintaining water quality, and only if it's very rainy.
C) Forests play a major role in reducing water pollution from runoff and in maintaining soil fertility.
D) Without plants, the animal population plummets, but this helps conserve water and nutrients in the system.
E) Plants decompose very slowly and release their nutrients back to the soil.