Parts of the atmosphere

What are the two most abundant gases in the Earth's atmosphere?

• Nitrogen and oxygen

• Carbon dioxide and helium

• Argon and neon

• Water vapor and dust

Which process is believed to have added free oxygen to the Earth's early atmosphere?

• Volcanic activity

• Photosynthesis

• Radiation from the Sun

• Decomposition of organic matter

What is the primary function of the Earth's atmosphere in relation to solar radiation?

• It absorbs most of the Sun's harmful ultraviolet radiation.

• It traps the Sun's warming rays, creating a greenhouse effect.

• It converts the Sun's energy into chemical energy through photosynthesis.

• It reflects the Sun's rays back into space, keeping the planet cool.

What is the main difference between the Earth's atmosphere and the atmospheres of other planets and moons?

• The Earth's atmosphere contains a greater variety of gases.

• The Earth's atmosphere is much thicker and denser.

• The Earth's atmosphere is the only one to contain free oxygen.

• The Earth's atmosphere is the only one to support life.

Why do mountains have colder temperatures at the top compared to the bottom?

• The air is thicker at the bottom.

• The air is thinner at the top.

• The sun shines more at the top.

• There is more greenhouse gas at the top.

What are the high-speed winds at the top of the troposphere called?

• Hurricanes

• Tornadoes

• Jet streams

• Thunderstorms

What gas in the troposphere helps keep the Earth warm?

• Oxygen

• Nitrogen

• Carbon dioxide

• Water vapor

The stratosphere is important because it has:

• Lots of clouds

• Planes that can fly there

• Ozone that protects us from UV rays

• Sudden and violent changes

What kind of chemicals have been linked to a decline in the ozone layer?

• Rainwater

• Perfumes

• Chlorofluorocarbons (CFCs)

• Volcanic gases

The ozone layer in the stratosphere is:

• Thicker at the equator

• Evenly spread out

• Thicker at the poles

• Uneven and thinner at the poles