Answer:
There are two reasons: at higher altitudes, there is less air pushing down from above, and gravity is weaker farther from Earth's center. So at higher altitudes, air molecules can spread out more, and air density decreases
Are their any multiple answer's ?
A vast, flat,treeless arctic region of Europe,Asia,&& North America in which the subsoil is permanently frozen.
I think the answer is B.
Because one of the factors that has prevented it from being a more unified country is its geography. It's rugged, mountainous. It's very difficult for any invading army to develop or control it.
