Carbon + Nitrogen Cycle

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?

• Burning wood

• 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 activities with a negative 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

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

• Plants

• Bacteria

• Animals

• Humans

Which process does not produce carbon dioxide?

• Photosynthesis

• Burning Fossil Fuels

• Animal respiration

• Plants decaying

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

• Stay the same

• Increase

• Decrease

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?

• Respiration and photosynthesis

•  Decomposition and respiration