Nitrogen Enrichment of Ecosystems by Human Activity Is Largely Driven

Multiple Choice

Nitrogen enrichment of ecosystems by human activity is largely driven by

A) addition of nitrogen fertilizers.
B) nitrogen pollution from burning of fossil fuels.
C) nitrogen fixation by bacteria in landfills.
D) Both addition of nitrogen fertilizers and nitrogen pollution from burning of fossil fuels.
E) Both addition of nitrogen fertilizers and nitrogen fixation by bacteria in landfills.