What term refers to the outright refusal to participate in a survey?

In 2009 approximately what percentage of Mexico's entire population lived in the greater Mexico City area?

A. 23 percent B. 5 percent C. 40 percent D. 10 percent

Women support the average Democrat __________

a. about 15 percent less than do men b. 5 to 7 percent less than do men c. 5 to 7 percent more than do men d. about 15 percent more than do men