Which of the following is an appropriate unit to measure large distances across the universe? an astronomical unit a kilometer a light year a mile

A light year

Explanation:

Yeah, if you're measuring across the universe, a light year is the only really appropriate unit of measurement you could be using. Given the vast amount of distance that light would cover in a year, one light year is extremely large.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.