1. Global warming is caused by the ______.

Excessive release of carbon dioxide into the atmosphere Circulation of oxygen in the atmosphere Release of hydrogen into the atmosphere Circulation of nitrogen in the atmosphere

2. Photosynthesis is important to living organisms because it produces ______.

Glucose and oxygen Glucose and carbon dioxide Oxygen and carbon dioxide Water and carbon dioxide

3. In a carbon cycle diagram, plants absorb carbon dioxide from the atmosphere through which process?

Photosynthesis Respiration Decomposition Combustion

4. Which of the following is a natural cycle that occurs in the environment?

The carbon cycle The traffic cycle The school timetable The market cycle

5. During respiration, living organisms ______.

Take in oxygen and release carbon dioxide Take in carbon dioxide and release oxygen Release nitrogen only Take in only water

6. Which of the following is a human activity that disrupts the carbon cycle?

Burning of fossil fuels Planting trees Recycling waste Conserving water

7. Which of these is an effect of the disruption of the carbon cycle on the environment?

Global warming and rising temperatures Cooler temperatures worldwide Increased oxygen levels only No effect at all

8. Reducing the amount of forest cover through deforestation contributes to ______.

An increase in carbon dioxide levels in the atmosphere A decrease in carbon dioxide levels No change in the atmosphere An increase in oxygen only

9. Deforestation and the burning of vegetation can lead to which of these effects?

Air pollution and depleted vegetation cover Increased vegetation cover Cooler climates only No effect on the environment

10. Which gas is mainly responsible for trapping heat in the atmosphere, acting like a greenhouse?

Carbon dioxide Nitrogen Hydrogen Helium