Question

drag the correct label to each location. the labels can be used more than once.
identify each example on the diagram as a carbon source or a carbon sink.
carbon sink carbon source
the carbon cycle
carbon dioxide co₂ atmosphere
photosynthesis combustion
respiration
plants animals factories power stations vehicle emissions
respiration energy
fossil fuels coal oil natural gas

Explanation:

• Photosynthesis (Plants): During photosynthesis, plants take in \( \text{CO}_2 \) from the atmosphere and convert it into organic matter, storing carbon. So this is a carbon sink.
• Combustion (Factories, Power Stations, Vehicle Emissions): Combustion of fossil fuels or other materials releases \( \text{CO}_2 \) into the atmosphere, adding carbon. So this is a carbon source.
• Fossil Fuels (and the arrow from Animals/Plants to Fossil Fuels): Fossil fuels store carbon (they are a long - term carbon sink in their unburned state, but when considering the cycle, the process of them being a source when burned, and the deposition of organic matter from plants/animals to form fossil fuels is a sink - like process in the long - term storage. But in the context of the cycle, the "Fossil Fuels" box (and the arrow into it) represents the storage of carbon from dead plants/animals, so it is a carbon sink (for the storage part; when burned, it's a source, but the box here is about the storage). Also, the respiration from animals and plants releases \( \text{CO}_2 \), so the respiration arrows (from animals/plants to atmosphere) are sources, but the "Fossil Fuels" box (the one with the arrow from plants/animals) is a sink.

Answer:

• Photosynthesis (Plants): carbon sink
• Combustion (Factories, Power Stations, Vehicle Emissions): carbon source
• Fossil Fuels (and the arrow from Plants/Animals to Fossil Fuels): carbon sink
• Respiration (from Plants/Animals to Atmosphere): carbon source