to measure the density of Earth's atmosphere. to learn more about stars and planets. to observe the surface of the Moon. to better understand Earth.
I gave my students this multiple choice question: A telescope would be used for all the following except

Only one answer is correct among these 4 choices:
- to measure the density of Earth's atmosphere.
- to learn more about stars and planets.
- to observe the surface of the Moon.
- to better understand Earth.

Could you tell me which one is correct?

to measure the density of Earth's atmosphere.