Which would be a result of increased deforestation?

A. The amount of oxygen in the atmosphere would increase.

B. Global warming would increase due to higher CO2 levels.

C. Nitrogen fixation would increase as bacteria died.

D. Fossil fuels would become more common underground.

Global warming would increase due to higher CO2 levels. (B.)

B. Global warming would increase due to higher CO2 levels. is the correct answer.

Explanation:

deforestation result in a Global warming would increase due to higher CO2 levels.

deforestation is cutting or removal of trees, When all the forest is cleared then only a few trees are left to remove the gases such as carbon dioxide and the carbon stored in the trees is then released into the air in the form of carbon dioxide which causes global warming.