Which term describes the movement of carbon from the nonliving environment into living things and back?

Which term describes the movement of carbon from the nonliving environment into living things and back?

• A. Carbon Cycle
• B. Carbon Sink
• C. Nitrogen Cycle
• D. Soil

Answer: (A)

Movement of carbon from the nonliving environment into living things and back is described by the carbon cycle. This cycle shows how carbon moves between air, water, rocks, and living organisms: plants pull carbon dioxide from the atmosphere during photosynthesis to build organic matter; animals obtain carbon by eating plants or other organisms and release carbon back through respiration; when organisms die and decompose, carbon returns to the soil and atmosphere. The cycle also includes long-term storage in carbon sinks like forests, soils, and oceans, and exchanges with oceans and sediments. A carbon sink is a place that stores carbon for extended periods, part of the cycle but not the entire process. The nitrogen cycle and soil are not describing carbon movement, so they don’t fit as the overall concept here.

Movement of carbon from the nonliving environment into living things and back is described by the carbon cycle. This cycle shows how carbon moves between air, water, rocks, and living organisms: plants pull carbon dioxide from the atmosphere during photosynthesis to build organic matter; animals obtain carbon by eating plants or other organisms and release carbon back through respiration; when organisms die and decompose, carbon returns to the soil and atmosphere. The cycle also includes long-term storage in carbon sinks like forests, soils, and oceans, and exchanges with oceans and sediments. A carbon sink is a place that stores carbon for extended periods, part of the cycle but not the entire process. The nitrogen cycle and soil are not describing carbon movement, so they don’t fit as the overall concept here.