Florida Biology EOC Practice Test

Where is carbon stored when living things die and decompose?

1. In the atmosphere

2. In oceans

3. In rocks and soil

4. In groundwater

The correct answer is: In rocks and soil

When living organisms die and decompose, carbon is primarily stored in the soil and rocks as organic matter. During decomposition, microorganisms break down the organic material, releasing nutrients that enrich the soil. This process also leads to the formation of humus, which is rich in carbon. The carbon that is stored in the soil can remain there for varying lengths of time, depending on environmental conditions and the composition of the organic material. Over longer geological timescales, some of this carbon can be further buried and eventually converted into fossil fuels or carbonate minerals within rocks, contributing to the carbon cycle. While carbon can also be found in the atmosphere and oceans, the decomposing organisms predominantly contribute carbon to the soil and rock formations, making this option the most accurate answer. Groundwater can contain dissolved organic carbon, but it is not the primary storage location for carbon from decomposed living things.