Choose from:
A). bushes;
B). humans;
C). animals;
D). soils;
E). disease;
F). legumes;
G). mammals;
H). Birds;
Given those answer options, answer the question: Fact 1: Soil can be depleted of nutrients. Fact 2: An important nutrient commonly added to soil is nitrogen. Given the two facts above, nitrogen depletion is a condition of some:?
A:
D).