Question

How have humans changed the global nitrogen cycle?

A. They have greatly decreased the amount of fixed nitrogen.
B. They have raised the speed at which nitrogen travels through the
cycle.
C. They have lowered the speed at which nitrogen travels through the
cycle.
D. They have greatly increased the amount of fixed nitrogen.

Answer 1

D

Step-by-step explanation:

Humans activities, such as making fertilizers and burning fossil fuels, have significantly altered the amount of fixed nitrogen in the Earth's ecosystems.