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.

landlessness of ordinary people

^^something like that^^^

ask an adult bc this is too hardcore