Terrestrial planets, like Earth, are made up of rock and metal. ...

[tfester]

Terrestrial planets, like Earth, are made up of rock and metal.
 
  a. True
  b. False
  Indicate whether the statement is true or false

Question 2

Molecular clouds are mapped using _____ gas instead of the most-abundant hydrogen because itradiates at radio wavelengths more efficiently.
 
  a. oxygen III
 b. oxygen II
 c. helium II
 d. carbon monoxide
  e. carbon dioxide

[kristenb95]

Answer to Question 1

True

Answer to Question 2

d