Carbon cycle

Carbon dioxide is returned to the atmosphere primarily by the

• A) eruption of volcanoes.

• B) respiration of consumers.

• C) fallout from solar flares.

• D) process of photosynthesis.

Burning of fossil fuels has changed the atmosphere by

• A) producing a hole in the ozone.

• B) reducing the CFCs in the atmosphere.

• C) increasing the concentration of carbon dioxide.

• D) increasing the concentration of ozone in the atmosphere.

In the carbon cycle, carbon is transferred from animals to decomposers in all of the following ways EXCEPT

• A) as waste.

• B) in dead carcasses.

• C) as carbon dioxide.

• D) in scraps of discarded food.

CO2 is returned to the atmosphere by all methods EXCEPT

• A) combustion.

• B) decomposition.

• C) photosynthesis.

• D) respiration.

The burning of fossil fuels by cars and factories has most affected the ______________ cycle.

• A) carbon

• B) hydrogen

• C) nitrogen

• D) water

Which pollutant would probably NOT DIRECTLY harm most plants, despite having a negative impact on human populations and the environment?

• A) motor oil from automobile runoff

• B) acid rain from smoke stack emissions

• C) carbon dioxide from automobile exhaust

• D) salt pollution from fertilizers and erosion

The diagram shown above, illustrates the _______ cycle.

• A) carbon

• B) nitrogen

• C) phosphorus

• D) water

What two processes fuel the carbon cycle?

• A) transpiration and transport

• B) photosynthesis and transport

• C) cellular respiration and transpiration

• D) cellular respiration and photosynthesis

Scientists previously referred to the long-ago deposited plant and animal remains, now buried, compacted, and transformed into coal and oil, as the dead-end of the carbon cycle. Since the Industrial Revolution, that would be an inaccurate statement. Why?

• A) The carbon found in coal and oil is released back into the atmosphere as carbon dioxide.

• B) Factories burning coal and oil deposit industrial wastes that add carbon back into the environment.

• C) The carbon stored in the coal and oil combines with water in the atmosphere and falls back to Earth.

• D) The combustion of coal and oil releases nitrogen by-products into the environment to be used again by man.

Carbon is a major component of all organic compounds, including carbohydrates, lipids, proteins, and nucleic acids. Carbon dioxide is continually exchanged between the atmosphere and oceans. What geological process returns carbon to the atmosphere in the form of carbon dioxide?

• A) respiration

• B) transpiration

• C) volcanic activity

• D) decomposition of marine sediments