During the last twenty years, which category of the U.S. population has experienced the largest gains in average income?
a. The lowest-paid 20 percent
b. The middle 20 percent
c. The highest-paid 20 percent
d. All income categories have experienced about the same level of upward social mobility.
Question 2
During the last three decades, the real income of African American families in the United States has ________
a. gone down a lot.
b. kept pace with the gains made by white people.
c. gone up a lot.
d. changed very little.
Animal extinctions and human population growth.
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