human
Question: Planting legumes in order to add nitrogen to soil most likely causes

Choices:
A) a decrease in the amount of acid rain.
B) an enrichment in the fertility of the soil.
C) an increase in the ratio of nitrogen to oxygen in the system.
D) a reduction in the soil's ability to manufacture its own nitrogen.
gpt
The correct answer is 1: an enrichment in the fertility of the soil..