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

What does not produce carbon dioxide?

• Photosynthesis
• Burning Fossil Fuels
• Cellular respiration

• Plants decaying

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

• respiration and photosynthesis
•  decomposition and respiration

In the carbon cycle, producers take in the gas __

• carbon dioxide
• oxygen
• nitrogen
• carbon monoxide

Which of the following removes carbon from the atmosphere?

• Combustion
• Respiration
• Photosynthesis
• Death

Combustion is another word for __________.

• Transportation
• Respiration
• Fossil Fuels
• Burning

Carbon can be found in...

• The atmosphere
• Soil
• Fossil fuels
• All of the above

The diagram shows the flow of organic molecules through an ecosystem. What two processes are identified by the labels X and Y?

• X : Respiration
  Y : Predation
• X : Adaptation
  Y : Decomposition
• X : Fermentation
  Y : Nitrogen Fixation
• X : Decomposition
  Y : Respiration

Plants reduce the amount of carbon in the atmosphere by taking it in and converting it into...

• oxygen

• glucose (sugar)

• water

• methane