Which of the following if not a geographic boundary of europe
a) the atlantic ocean
b) the ural mountains
c) the alps
d)the mediterranean sea

Saudi arabiahope this

Build a market-oriented economy;

Airplanes usually fly in the lower part of the stratosphere - there is nearly no water vapor and it's very dry, so it to avoid big turbulences. it's about 8-10 kilometers above ground (depending on weather conditions, region etc.)