What is the term for the movement of carbon from the nonliving environment into living things and back?

• A. limiting factor
• B. carbon cycle
• C. organ system
• D. Tides

Answer: (B)

The term for moving carbon from the nonliving environment into living things and back is the carbon cycle. This cycle describes how carbon travels through air, water, soil, and living organisms. Plants take in carbon dioxide during photosynthesis to make sugars, moving carbon from the atmosphere into plant tissue. Animals obtain carbon by eating plants or other animals, transferring it into their bodies. Through respiration, decomposition, and microbial activity, carbon is released back into the air or soil as carbon dioxide or stored in organic matter, and the oceans exchange carbon with the atmosphere as well. Human activities, like burning fossil fuels, add extra carbon to the cycle, altering balances.

Other terms don’t fit this idea: a limiting factor is about something that restricts growth, an organ system is a group of organs in an organism, and tides refer to rhythmic rises and falls of ocean water.