Within Earth's atmosphere the ozone layer is located:
A) in the troposphere.
B) between the troposphere and the stratosphere.
C) in the stratosphere.
D) between the stratosphere and the mesosphere.
E) in the mesosphere.
Question 2
What is the percentage of Earth's atmosphere (by volume) that is carbon dioxide (CO2)?
A) 78
B) 21
C) 3
D) 0.9
E) 0.03
