Which of the following explains why mountain tops are a great
place for observatories?
A. They have less gravity.
B. There is less magnetic interference.
C. The weather is calmer.
D. There is less atmosphere above them.

D, there is less atmosphere above them

Explanation:

When telescopes are at a high elivation, they get away from the distortion of starlight due to the atmosphere and because of the elevation, the telescopes are above most of the water vapor in the atmosphere, so infrared astronomy can be done.

since there isn't any suggested answers i will give you the reason and hopefully you can figure it

south africa, or rather all of africa, has not been in the location in which it is nowadays throughout the geological past. after the super-continent pangaea started to break apart, gondwanaland, in which was africa, moved further south, and parts of it came to be very close to the south pole. because the climate in this part of the world is very cold due to the very dispersed sun rays in there, what is now south africa, started to freeze, and the conditions were right for the formation of glaciers. the glaciers existed up until the period when gondwanaland started to break apart and what is now africa started to move towards north, sp it warmed up and the glaciers melted.