Author Question: Which of the following is considered a variable gas in Earth's atmosphere? a. water vapor b. ... (Read 62 times)

waynest · **on:** Jul 13, 2018

Which of the following is considered a variable gas in Earth's atmosphere?
a. water vapor
b. nitrogen
c. oxygen
d. argon
e. helium

Question 2

In a volume of air near Earth's surface today, ____ occupies 78 percent and ____ nearly 21 percent.
a. nitrogen; oxygen
b. hydrogen; oxygen
c. oxygen; hydrogen
d. nitrogen; water vapor
e. hydrogen; helium