When diminishing marginal utility sets in, total utility must be negative

If the income elasticity of demand for a good is 2, then when income rises 10 percent, the quantity demanded

A) increases 2 percent. B) increases 20 percent. C) decreases 2 percent. D) decreases 20 percent. E) increases 12 percent.

Which of the following most accurately describes changes in life expectancy?

a. Life expectancy was relatively low until 1750, after which it increased rapidly. b. Life expectancy has increased steadily during the past 6,000 years. c. Life expectancy was low until after World War II, after which it increased very quickly. d. Life expectancy has exhibited significant cyclical patterns of growth and decline.