[20 pts] Carbon is the chemical backbone of all life on Earth. While the total amount of carbon we have on Earth does not change, carbon moves between the atmosphere and other carbon reservoirs such as rocks (solid and interior Earth), land (biosphere), and oceans, greatly influencing the Earth’s climate. 

a. [10 pts] Explain how weathering of rocks can act as stabilizing (negative) feedback on atmospheric CO₂, including two factors that influence the rate of weathering.

c. [10 pts] Explain what role carbon plays in the Earth's energy balance.