Which of the following is a statement about carbon sinks?

• A. They are processes that release CO2
• B. They are not related to climate
• C. They release carbon into the atmosphere
• D. They remove CO2 from the atmosphere and store it

Answer: (D)

Carbon sinks are reservoirs or processes that take in more carbon dioxide than they release, helping regulate climate by lowering the amount of CO2 in the atmosphere. Plants capture CO2 during photosynthesis and store carbon in their wood and roots; soils accumulate carbon as organic matter from decaying plants and microbes. The ocean also acts as a sink, absorbing CO2 and storing it as dissolved carbon or in carbonate minerals. Because of these uptake and storage processes, carbon sinks remove CO2 from the atmosphere and hold onto it, which is why that statement is the best description. The other ideas describe carbon sources or claim no climate relevance, which doesn’t fit how sinks operate.