Answer the following questions. You will receive immediate feedback when you select your answer or when you click on the green check mark (). When you are finished, click the How Did I Do? button to see your score.

For questions 1 to 3, refer to Figure 7.1.1.

Figure 7.1.1, Distribution of Earth's Water. (“Where is Earth's Water Located?” USGS, 2006)

1. How much of the earth's water is freshwater?
   
   

2. How much of the freshwater is permanently frozen?
   
   

3. How much of the freshwater is stored underground?
   
   

For questions 4 and 5, refer to Figure 7.1.2.

Figure 7.1.2, How much of Earth's water is usable to humans? (USGS, 2006)

4. What percentage of the earth's water is available for use by humans?
   
   

5. Where is most freshwater located?
   
   

For questions 6 to 8, refer to Figure 7.1.3.

Figure 7.1.3, Estimate of Global Water Distribution. (“Water Resources,” P.H. Gleick, Encyclopedia of Climate and Weather, 1996)

6. Compare soil moisture to atmospheric moisture; which of the two contains the most moisture?
   
   

7. Compare freshwater lakes to saline water lakes; which of the two types of lakes contains the most water?
   
   

8. What is the largest source of freshwater that is above the ground?
   
   

9. Since almost all of our drinking water comes from rivers, what could be the result if industries and individuals add contaminants such as chemicals or other waste products to rivers?
   
   

10. There is concern about chemicals and petroleum products that are being allowed to seep into the ground. How could this seepage affect our water supply?