Question

1. which human activities add extra carbon to the atmosphere? a. photosynthesis b. combustion of fossil fuels c. rock formation

Explanation:

Photosynthesis removes carbon dioxide from the atmosphere and uses it to make organic compounds. Rock formation is a geological process not directly related to adding carbon to the atmosphere. Combustion of fossil fuels by humans releases large amounts of carbon - stored for millions of years - into the atmosphere as carbon dioxide.

Answer:

b. Combustion of fossil fuels