The biosphere is all living things on earth
Answer:
The main reason airplanes fly in the stratosphere is because this is where the least amount of turbulence is found. In addition, because the stratosphere is very dry, there are fewer clouds in this layer, making for a much smoother ride overall.
Explanation:
In case of drastic emergency or fallout if the us were to stand alone it would need supplies it could get on its own
