Task: Class Definition Understanding (ontology: Earth_Environment/EnvironmentOntology)

Which of the following definitions best describes 'humus'?

A. A the concept is a naturally occurring solid aggregate of one or more minerals or mineraloids.
B. An environmental material which is solid, jelly-like, and exhibits no flow when in steady state material and which contains liquid dispersed in and held in place by cross-linked structures of a solid medium.
C. Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
D. Organic material which is in a solid phase and contained in sedimentary rock.

Answer: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.