How does the burning of fossil fuel and deforestation effect the environment?

the burning of fossil fuel and deforestation effect the envrionment because when we burn fossil fuel we pollute the air with smoke and toxins which are not healthy for the body to intake nor for plants decreasing their health. Deforestation will lead to losing oxygen we need to breath since trees and plants produce oxygen and take carbon dioxide which we give off and if we loose those trees we will not be able to breath