Requiring all firms to reduce emissions by the same percentage is

The existence of wage-related rent

a. is explained by the fact that people have different opportunity costs b. is explained by the fact that some people who work also own land c. indicates that wage rates can be higher than rents d. is a contradiction because workers' incomes derive from labor e. result from the different productivities of workers

Profit-maximizing firms enter a competitive market when existing firms in that market have

a. total revenues that exceed fixed costs. b. total revenues that exceed total variable costs. c. average total costs that exceed average revenue. d. average total costs less than market price.