Answer: The trees are the soul source of oxygen on land and cutting them would decrease the amount of oxygen.
Step-by-step explanation:
Ten miles of land completely covered by trees and plants is cut down. This will highly affect the amount of oxygen in the environment.
The plants are the main organism which adds oxygen to the atmosphere and removes carbon dioxide.
The soul source of oxygen will be depleted if trees are cut down so there will be a decrease in the concentration of oxygen in the atmosphere.