Astronomers build telescopes on tops of mountains because a. ...

[Haya94]

Astronomers build telescopes on tops of mountains because
 
  a. there is less air to dim the light.
  b. the seeing is better.
  c. CCDs work better when there is less oxygen in the air.
  d. all of the above
  e. a and b

Question 2

Molecular clouds are mapped using CO instead of hydrogen because CO is much more abundant than hydrogen in molecular clouds.
 
  Indicate whether the statement is true or false

[dantucker]

Answer to Question 1

E

Answer to Question 2

F