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Humans burn fossil fuels and wood, releasing carbon dioxide into the atmosphere. This carbon dioxide is then absorbed by trees for photosynthesis. These processes are contributory to which chemical cycle?

• The carbon cycle

• The water cycle

• The nitrogen cycle

• The phosphorous cycle

How does the human body return carbon to the atmosphere in the carbon cycle?

• Waste products

• Photosynthesis

• Cellular respiration

• Formation of glucose

In the carbon cycle, animals can release carbon back into the cycle through __________ or through __________.

• burning . . . photosynthesis

• fixation . . . decomposition

• decomposition . . . photosynthesis

• respiration . . . decomposition

• respiration . . . photosynthesis

Which of the following is an example of human impact on the carbon cycle?

• The increased production of methane gases from cattle farms

• The burning of fossil fuels

• The cutting down of trees for lumber

• Driving automobiles

• All of the above

If a forest fire occurs, what will happen to the carbon in the forest?

• It will go into the soil

• It will go into the atmosphere

• It will runoff into nearby streams and rivers

• It will be destroyed

Where does all the carbon in organisms (living things) originate from?

• Earth's atmosphere

• Rocks

• Water

• Soil

How do organisms (living things) move carbon through the carbon cycle?

• Respiration only

• Decomposition only

• Photosynthesis, respiration, and decomposition

• Decomposition and sedimentation

• Respiration, decomposition, sedimentation, and photosynthesis

By what method is the majority of carbon moved from the lithosphere (upper part of Earth's crust) to the atmosphere?

• Weathering

• Deposition

• The burning of fossil fuels

• Respiration

By what method is the majority of carbon moved from the lithosphere (upper part of Earth's crust) to the atmosphere?

• Weathering

• Deposition

• The burning of fossil fuels

• Respiration

What kind of organism takes out the most carbon from the atmosphere?

• Plants

• Bacteria

• Animals

• Humans