Chapter 4 Review

1. The advance of desert-like conditions into areas that previously were fertile is called Desertification Crop rotation Nutrient depletion Land reclamation

2. Which of the following is a biodegradable waste? A glass jar A metal can An apple core A plastic bag

3. The water and waste materials washed down toilets and sinks are called Pesticides Sewage Industrial chemicals fertilizers

4. A device that removes pollutants from emissions is a Scrubber Catalytic converter Filter CFC substitute

5. Which gas is thought to be one of the causes of global warming? Radon Ozone Carbon dioxide Carbon monoxide

6. Describe two techniques for preventing nutrient depletion. Leave fields fallow (unplanted) Crop rotation

7. What is a drought? A period when less rain than normal falls on an area.

8. What is one way that communities can encourage residents to produce less solid waste? Curbside recycling with curbside pick up. Recycling bins in public places. Offer money for recycled waste

9. Explain how a person might be exposed to a hazardous substance that was buried underground many years ago? Hazardous substance may have leached out of the soil and seeped into the groundwater, thus contaminating the water supply.

10. How can a small oil spill in the ocean be naturally cleaned up? Bacteria can feed on the oil and break it up.

11. How does acid rain form?

12. What role does carbon dioxide play in the greenhouse effect?

13. In strip mining, a layer of soil is removed to expose a resource, such as coal, underneath. What methods could be used to restore the damaged land? Topsoil and subsoil could be replaced in original order. Then the area can be replanted.

14. Why is it unsafe to bury or incinerate radioactive waste? Radioactive waste remains dangerous for thousands of years. Burning the waste might pollute the air, and burying it could pollute the ground water.

15. Would you expect the levels of photochemical smog to be worse in cities or in rural areas? Cities would be worse because the major sources of smog are the gases emitted from motor vehicles and factories, which are more concentrated in cities.

16. What is represented by the gray haze in the diagram 16. What is represented by the gray haze in the diagram? Why is it confined to the cool layer? The gray haze is smog. It is confined to the cool layer because a temperature inversion prevents the polluted air from rising.

18. What was the average level of carbon dioxide in the atmosphere at the beginning of the study? At year 20? 328 ppm at the beginning About 363 ppm in Year 20

19. How much did the average level of carbon dioxide increase during the study? 35 ppm