Humus:
A) is the material always comprising the topmost soil horizon.
B) is dark, organic-rich material formed by bacterial decay.
C) is leaf-litter.
D) must include sediments.
E) none of the above

Question

Quizplus · Accepted Answer

Humus is dark, organic-rich material that forms in soil when plant and animal matter decays. Bacteria, fungi, and other organisms break down this matter, leaving behind humus, which enriches the soil with nutrients.