Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
Telescopes on Earth all have one big problem: incoming light must pass through the atmosphere. This blocks some wavelengths of radiation. Also, motion in the atmosphere distorts light. You see this when you see stars twinkling in the night sky. Many observatories are built on high mountains. There is less air above the telescope, so there is less interference from the atmosphere. Space telescopes avoid problems from the atmosphere completely since they orbit outside the atmosphere.


Question: Many observatories are built on high mountains to avoid interference from what?
the atmosphere
The atmosphere.