Which atmospheric layer is known for reflecting radio waves back to Earth?
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Thermosphere
Answer: d) Thermosphere

The primary cause of photochemical smog is:
a) Vehicle emissions
b) Industrial emissions
c) Natural gas leaks
d) Volcanic activity
Answer: a) Vehicle emissions

The gas primarily responsible for the formation of acid rain is:
a) Methane
b) Sulfur dioxide
c) Nitrogen
d) Carbon dioxide
Answer: b) Sulfur dioxide

Which of the following layers contains the most atmospheric water vapor?
a) Stratosphere
b) Mesosphere
c) Troposphere
d) Thermosphere
Answer: c) Troposphere

What effect does increasing levels of carbon dioxide have on Earth’s climate?
a) Cooling
b) Warming
c) No effect
d) Depletion of the ozone layer
Answer: b) Warming

Which layer of the atmosphere is also known as the ionosphere?
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Thermosphere
Answer: d) Thermosphere

Which gas in the atmosphere is vital for the survival of aerobic organisms?
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Argon
Answer: b) Oxygen

What is the function of the mesosphere in Earth’s atmosphere?
a) To absorb ultraviolet radiation
b) To burn up meteoroids
c) To trap heat
d) To support life
Answer: b) To burn up meteoroids

Which gas is primarily involved in the formation of ground-level ozone?
a) Nitrogen
b) Oxygen
c) Carbon monoxide
d) Nitrogen oxides
Answer: d) Nitrogen oxides

Which gas is a secondary pollutant formed by the reaction of sunlight with primary pollutants?
a) Ozone
b) Carbon dioxide
c) Nitrogen
d) Sulfur dioxide
Answer: a) Ozone