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

• Hydrosphere
• Atmosphere
• Biosphere
• Geosphere

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

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

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

• respiration and photosynthesis
•  decomposition and respiration

How does the carbon in grass become part of a lion?

• The lion eats the grass
• Carbon from grass doesn't end up in a lion. 
• The carbon ends up in the lion's food chain. 
• The lion breathes in carbon given out by the plant

Define the process shown here:

• Carbon Cycle
• Respiration
• Photosynthesis
• Decomposition

What does this image mean?

• Sugar
• Carbon dioxide
• Water
• Methylbromine

True or False:  All of the carbon in existence is continually recycled in the carbon cycle.

• True
• False

True or False:  Animals decomposing into the ground increases the amount of carbon in the soil.

• True
• False

The global carbon cycle involves which factors?

• the flow of carbon matter and energy from one reservoir to another
• the natural processes of photosynthesis and respiration
• a holding place for carbon, including the ocean, terrestrial living organisms, soils, sediments and atmosphere
• all of the above

Which natural process breaks down dead matter into its chemical and mineral components that can be used by other organisms?

• photosynthesis
• respiration
• decomposition
• greenhouse effect