A carbon sink is defined as...

• A. A body or process that removes carbon dioxide from the atmosphere and stores it
• B. A natural place where carbon is produced
• C. A machine that filters air
• D. A place where carbon is released into the atmosphere

Answer: (A)

A carbon sink is any natural reservoir or process that removes carbon dioxide from the atmosphere and stores it for long periods. This helps keep atmospheric CO2 levels from rising too fast. Forests take CO2 out of the air through photosynthesis and store it as biomass; oceans absorb CO2 and form carbonates; soils accumulate organic carbon from decaying matter. The key idea is removal and storage of CO2, not production or release. The other options describe producing carbon, filtering air, or releasing carbon into the air, which aren’t sinks.