Carbon in a Global Ecosystem

What have scientists around the world discovered about Earth's atmosphere?

• A decrease in the amount of carbon dioxide

• An increase in the amount of carbon dioxide

• No change in the amount of carbon dioxide

• A decrease in the amount of oxygen

What may the increase in carbon dioxide in our atmosphere cause?

• Localized effects on small communities

• Worldwide effects on climate and oceans

• Improvements in air quality

• Decrease in global temperatures

What is one source of carbon dioxide mentioned in the text?

• Solar panels

• Wind turbines

• Factories burning fossil fuels

• Photosynthesis in plants

What does the graph titled "Atmospheric CO2 at Mauna Loa Observatory" show?

• The stability of carbon dioxide levels over 60 years

• The decrease of carbon dioxide levels over 60 years

• The fluctuation of carbon dioxide levels over 60 years

• The increase of carbon dioxide levels over 60 years

What is carbon dioxide in the atmosphere primarily composed of?

• Carbon from living organisms

• Carbon from fossil fuels

• Carbon from the ocean

• Carbon from outer space

Why are coal, oil, and gas called "fossil fuels"?

• They are derived from ancient artifacts

• They are found only in fossils

• They are composed of carbon-rich matter from plants and animals that died millions of years ago

• They are fuels used exclusively for generating fossils

What happens to the carbon that was in the plants and animals when they died and turned into fossil fuels?

• It disappears completely

• It turns into oxygen

• It remains as part of the fossil fuels

• It becomes part of the soil

What is the consequence of burning fossil fuels?

• It decreases the amount of carbon dioxide in the air

• It has no impact on the atmosphere

• It releases large amounts of carbon dioxide into the air

• It generates pure carbon

What is the primary reason that decomposers never broke down the dead matter of plants and animals that turned into fossil fuels?

• The matter was too hard to decompose

• The matter was buried deep underground

• The matter was already fossilized

• The matter was toxic to decomposers

What is the Earth in terms of ecosystems according to the text?

• An open ecosystem with unlimited carbon exchange

• A closed ecosystem with limited water and carbon exchange

• A semi-closed ecosystem with regulated carbon exchange

• An isolated ecosystem with no carbon exchange