Carbon 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?

• 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

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

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

• Stay the same

• Increase

• Decrease

What organisms form fossils?

• animals

• plants and animals

• CaCO2

• sedimentary rocks

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

• water
• nutrients
• air
• fossil fuels