__________ in Earth's atmosphere absorbs most ultraviolet ...

[Mr.Thesaxman]

__________ in Earth's atmosphere absorbs most ultraviolet radiation coming from the Sun.
 
  a. Methane b. Three bound oxygen atoms
  c. Water vapor d. Carbon dioxide

Question 2

A star's apparent magnitude is a measure of
 
  a. how bright it appears to us if it is at its actual distance.
  b. how bright it appears to us at a standard distance of 10 pc.
  c. its energy output per second compared to the Sun.
  d. its mass in solar masses.
  e. its surface temperature in Kelvin.

[aadams68]

Answer to Question 1

b

Answer to Question 2

a

[Mr.Thesaxman]

Thanks for the timely response, appreciate it

[sultansheikh]

YES! Correct, THANKS for helping me on my review