Carbon dioxide dominates the atmospheres of Venus and Mars, but ...

[Pineappleeh]

Carbon dioxide dominates the atmospheres of Venus and Mars, but on Earth most of it lies underground as ________.
 
  Fill in the blank(s) with correct word

Question 2

What are some advantages of radio telescopes over optical telescopes?
 
  What will be an ideal response?

[hanadaa]

Answer to Question 1

carbonate (or limestone) rocks

Answer to Question 2

Radio telescopes can be used day or night, they are much less affected by cloudy skies, and they open a new window to observe the Universe. They allow us to observe astronomical objects at a different wavelength than an optical telescope, thus giving an opportunity to compare and contrast the images.

[Pineappleeh]

Excellent

[samiel-sayed]

Thanks for the timely response, appreciate it