Carbon flux from fossil fuels in the cycle diagram

Steps:

• Identify the arrow or label representing carbon release from fossil fuel burning to the atmosphere.
• Read the numerical value directly associated with that specific flux.
• Confirm the unit is gigatons of carbon per year (GtC/yr).
• Select the matching choice from the options.

Why A is correct:

• The diagram explicitly labels the annual carbon movement from fossil fuels as 120 GtC/yr, matching the standard flux in global carbon cycle models.

Why the others are wrong:

• B: Overestimates the flux by 5 GtC/yr, not matching the diagram.
• C: Exceeds the diagram's value by 10 GtC/yr, possibly confusing with another cycle component.
• D: Far too high, likely summing multiple unrelated fluxes like total emissions.

Final answer: A