Which period was not a recession in the United States?

An "all you can eat" restaurant illustrates the economic principle:

a. of consumers' inability to maximize their total utility. b. that economic theory clearly breaks down under certain circumstances. c. that marginal utility is always positive. d. that consumers will stop eating when marginal utility is zero. e. that consumers will stop eating when total utility is zero.

Which of the following will contribute to higher wage rates for labor?

a. increased productivity b. increases in capital formation c. a decrease in the supply of labor d. all of the above