Which of the following is NOT a component of soil?

Explanation

Soil components are: mineral particles (sand, silt, clay – from weathered rock), organic matter (decomposed plant and animal material), water, and air.

Anything not in these categories is NOT a soil component. Living organisms in soil are part of the ecosystem but distinct from the four basic components.

The balance of these components determines soil quality. Ideal agricultural soil has about 45% minerals, 5% organic matter, 25% water, and 25% air.