Carbon Cycle

When humans burn fossil fuels, most of the carbon quickly enters the                       as carbon dioxide.

• Water
• Atmosphere
• Sun
• Air

Which one of these does not add CO2 to the atmosphere?

• cooking with gas
• planting trees
• burning wood
• riding in a bus

If the plant population decreased, the amount of carbon would _________.

• Stay the same
• Increase
• Decrease

Which of the following gases DOES NOT trap heat?

• carbon dioxide
• nitrogen
• water vapor
• methane

Which of the following gases DOES NOT trap heat?

• carbon dioxide
• nitrogen
• water vapor
• methane

Visible light reaches Earth’s surface while infrared light is trapped as heat. Which characteristic of Earth’s atmosphere causes this to happen?

• the hole in the ozone
• the greenhouse effect
• atmospheric pressure
• the inversion layer

Which of the following is the best conclusion that can be made from this graph?

• atmospheric carbon dioxide levels have been decreasing since 1960
• Hawaii has a lot of carbon dioxide
• humans have been working hard to decrease carbon dioxide levels
• atmospheric carbon dioxide levels have increased steadily since 1960

Visible light reaches Earth’s surface while infrared light is trapped as heat. Which characteristic of Earth’s atmosphere causes this to happen?

• the hole in the ozone
• the greenhouse effect
• atmospheric pressure
• the inversion layer

Since the mid- 1800's, _____________ activity has significantly altered the carbon cycle.

• animal

• plant

• unknown

• human

Carbon compounds move from plants to animals via the process of _______?

• Respiration
• Photosynthesis
• Ingestion (eating)
• Diffusion