1. Which of the following is one reason that wetlands are important?
Wetlands help control floods by absorbing extra runoff from
heavy rain.
b. Wetlands cause worse floods because water cannot be absorbed.
c. Wetlands make summers hotter and winters cooler.
d. Wetlands make good areas for farms, homes, and businesses.

2. Most of Earth's water (about 97 percent) is
a. freshwater in lakes and rivers.
b. salt water in the oceans.
c. in the form of snow or ice.
d. in the clouds.

3. Which of the following is a point source of water
pollution?
a. runoff from farms or streets
b. sediments from erosion
c. an oil spill from a tanker
d. acid rain from fuel emissions

4. Fertilizers and pesticides are examples of
a. agricultural wastes.
b. industrial wastes.
c. road runoff.
d. human wastes.

5. As water moves slowly through a wetland, some waste materials settle out, some wastes are absorbed by plants, and silt and mud is trapped by plant roots. In this way, wetlands act as natural
a. filters.
b. habitats.
c. tributaries.
d. artesian wells.

6. . In which type of wetland is acidic water
generally found?
a. marshes
b. bogs
c. mangrove forests
d. swamps

7. How have the Everglades been affected by urbanization
and development?
a. Water flow has remained about the same.
b. Habitats and wildlife have greatly declined.
c. Water quality and drainage has improved slightly.
d. Its ability to absorb flood waters has improved.

8. Which of the following is caused by convection
currents in Earth's mantle?
a. gravity
b. global warming
c. earthquakes
d. mountain erosion

9. Which of the following terms is used to
describe groundwater rising to the surface
due to pressure in the aquifer?
a. reservoir
b. saturated zone
c. water table
d. artesian well

10. People cannot use most of the
freshwater on Earth because it is in the
form of ____________________.
ice

11. Which of the following helps reduce water pollution?
a. effective cleanup of oil and gasoline spills
b. proper treatment of sewage
proper disposal of hazardous wastes such as
paint thinners and motor oil
d. all of the above

12. The water and human wastes that are
washed down sinks, toilets, and showers are called ___________.
sewage

13. Marshes, bogs, and ________________ are
examples of freshwater wetlands.
swamps

14. Wetlands provide habitats for many living things because of their sheltered waters and
a. large supply of nutrients.
b. thick layer of mud.
c. lack of insects.
d. ability to prevent floods.

15. A well in which groundwater rises because of pressure is called a(n)
a. artesian well.
b. geyser well.
c. spring well.
d. dry well.

16. Some people obtain their water from
underground layers of rock or sediment
called ____________________.
aquifer

17. People may not have enough water during
a(n) ___________________, a period when
rainfall is below normal.
drought

18. An area of land that is covered
with a shallow layer
of water during some or
all of the year is called a(n) ______________.
wetland

19. Wetlands act as natural _____________
by allowing waste materials to settle out and
by plants absorbing and trapping sediments.
filter

20. What are the three types of boundaries between Earth’s tectonic plates?
Convergent, divergent, and transform boundaries

21. Wetlands help prevent ____________________ by absorbing runoff from heavy rains.
flooding

22. What can a farmer at Point C do to prevent farm runoff from causing pollution at Points B and D?
The farmer can refrain from using pesticides and limit the use of chemical fertilizers. The farmer can also make sure that animal wastes do not seep into the ground or is washed by rain into the river.

23. Compare and contrast ponds and lakes.
Ponds and lakes both contain still water. Both form when water collects in hollows and low-lying areas. Both are habitats that support a wide range of organisms. In general, ponds are smaller and shallower than lakes. Sunlight usually reaches to the bottom of all parts of a pond, but not to the bottom of lakes. As a result, pond bottoms are covered with mud and algae, and plants grow throughout the pond. In a lake, the bottom is covered only with sand, pebbles, or rock, and plants only grow around the edges.

24. Why are convection currents in the mantle responsible for reshaping the Earth’s surface?
When plates separate, pass each other, or crash into each other they reshape the Earth’s surface.

25. Explain how convection currents work?
As a fluids temperature increases, it density decreases.
As a fluids temperature decreases, it density increases.

26. Which changes to Earth’s surface happen slowly? Which happen quickly?
Mountains, ridges, and ocean basins happen slowly.
Earthquakes and volcanic eruptions happen quickly.

27. How can pollutants that seep through the
ground at Point B affect the water at point D?
The pollutants may enter the groundwater
and then the river, and be carried by the river
to point D.

28. How can recycled evergreen trees help prevent water pollution?
People can recycle trees to prevent water erosion of wetlands. People build fenced-in areas in shallow, moving water. Then they put the trees inside the areas. The water slows down when it flows through the trees, which decreases erosion. The trees also collect sediments in the water. The sediments build up, so, over time, marshes are formed. These new marshes provide living space for many animals.

29. Describe two ways in which oil can cause water pollution.
Oil from an oil spill can pollute water in a river or the ocean. Oil can be stored in underground storage tanks and leak, polluting soil and groundwater.

30. Describe on way you can reduce water pollution at home.
Never pour chemicals down the drain or flush them down the toilet. Save these materials for the community's hazardous household waste collection.