The most abundant gas in the Earth’s atmosphere is:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Argon
Answer: c) Nitrogen

The layer of the atmosphere closest to Earth is called:
a) Stratosphere
b) Mesosphere
c) Troposphere
d) Thermosphere
Answer: c) Troposphere

Which layer of the atmosphere contains the ozone layer?
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Thermosphere
Answer: b) Stratosphere

Ozone in the atmosphere is important because it:
a) Warms the Earth
b) Cools the Earth
c) Absorbs ultraviolet radiation
d) Reflects sunlight
Answer: c) Absorbs ultraviolet radiation

The gas responsible for the greenhouse effect is:
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Argon
Answer: c) Carbon dioxide

Which of the following gases is a major contributor to acid rain?
a) Nitrogen
b) Oxygen
c) Sulfur dioxide
d) Methane
Answer: c) Sulfur dioxide

The process of converting atmospheric nitrogen into a usable form for plants is called:
a) Nitrogen fixation
b) Photosynthesis
c) Respiration
d) Combustion
Answer: a) Nitrogen fixation

The harmful effect of chlorofluorocarbons (CFCs) is:
a) Global warming
b) Ozone layer depletion
c) Acid rain
d) Smog formation
Answer: b) Ozone layer depletion

The primary cause of the thinning of the ozone layer is:
a) Carbon dioxide emissions
b) Chlorofluorocarbons (CFCs)
c) Sulfur dioxide
d) Methane
Answer: b) Chlorofluorocarbons (CFCs)

The atmospheric pressure is highest in the:
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Thermosphere
Answer: a) Troposphere