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

Which of the following definitions best describes 'soil organic matter'?

A. An astrononmical body part which delimited by physical discontinuities with its surroundings.
B. Ecozones delineate large areas of a planetary surface within which organisms have been evolving in relative isolation over long periods of time, separated from one another by geographic features, such as oceans, broad deserts, or high mountain ranges, that constitute barriers to migration.
C. Organic material in soil, which consists of plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by soil organisms.
D. A portion of the concept is a portion of environmental material primarily composed of the concept.

Answer: Organic material in soil, which consists of plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by soil organisms.