Why do some large commercial airlines fly in the stratosphere?

-Commercial jet aircraft fly in the lower stratosphere to avoid the turbulence which is common in the troposphere below. The stratosphere is very dry; air there contains little water vapor. Because of this, few clouds are found in this layer; almost all clouds occur in the lower, more humid troposphere.

hi there!

question - how does mountainous terrain affect settlements in a region? choose all answers that are correct.

groups trade with each other regularly.

people travel from settlement to settlement.

why: since they travel to go trade or visit it may be harder to get there because of the mountainous terrain.

hope this : )