Cycle Quiz

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

Which of the following add carbon dioxide to the atmosphere?

• volcanoes
• combustion of fossil fuels
• animal and plant respiration
• all of these

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

• water
• nutrients
• air
• fossil fuels

The average temperature of the surface of Earth has increased approximately 1°C in the past century. Which reason best explains this increase in temperature?

• lower levels of ozone in the atmosphere
• lower levels of nitrogen in the atmosphere
• higher levels of carbon dioxide and other greenhouse gases in the atmosphere
• higher levels of oxygen in the atmosphere

With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant________

• leaves

• food

• roots

• nutrients

Through food chains, the carbon that is in plants moves to the animals that eat them. When an animal eats another animal, carbon is ___________________.

• released

• transferred

• dissolved

• gone

Which process contributes carbon dioxide to the atmosphere?

• respiration

• photosynthesis

• tree farms

Which process removes carbon dioxide from the atmosphere?

• deforestation

• tree farms

• burning fossil fuels

• cellular respiration

Which of the following is correct?

• There is as much carbon on earth as when it was formed

• Carbon is being created whenever it is recycled

• Carbon is lost every time it is recycled

• Carbon changes to different forms and is never recovered