Up here topically a majority of our mountains and craters are results of volcanoes and earthquakes that are caused by moving tectonic plates. on the ocean floor the features are caused by the same things. there are under water mountain ranges and craters.
The answer is competition for natural resources will increase. More people means people will fight for limited natural resources. It’s the only one that seems logical. Oxygen will not increase since humans do not produce it, we cut down the trees and plants that do to build our houses. More land will not be available it will decrease as more people inhabit the planet and take up more space. People will use more fossil fuels because more people = companies take advantage to sell their product. They don’t care about the environment so if the demand goes up then they will supply more. Even though there’s a limited amount, therefore meaning that the overall amount will decrease.