Carbon Cycle

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

• Water
• Atmosphere
• Sun
• Air

How do living organisms return carbon to the atmosphere in the carbon cycle?

• photosynthesis

•  respiration

Organisms that do not decompose can be buried and become what?

• water
• nutrients
• air
• fossil fuels

With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant________

• leaves

• food

• roots

• nutrients

Which process contributes carbon dioxide to the atmosphere?

• respiration

• photosynthesis

• tree farms

Which of the following removes carbon from the atmosphere?

• Combustion
• Respiration
• Photosynthesis
• Death

Respiration is the process by which animals take in _____ and release _____ to make energy. 

• photosynthesis, air
• carbon, oxygen
• oxygen
• oxygen, carbon dioxide

How do animals get carbon?

• Photosynthesis

• They absorb it from the atmosphere

• The sun

• They eat other plants and animals

What is CO2?

• Air

• Oxygen

• Carbon Dioxide

• Dioxide

How is carbon returned to the soil?

• Burning fossil fuels

• Animal waste and decomposition

• Respiration