Which of the following explains why supply curves slope upward?

Question

Quizplus · Accepted Answer

Supply curves slope upward because of increasing marginal cost. As firms increase production output, they need to use resources that are progressively less and less suited to that purpose or add shifts that must be paid more than previous ones. As a result, the cost of producing each additional unit of output tends to increase, and the willingness of firms to supply that additional unit at any given price also increases.

Which of the Following Explains Why Supply Curves Slope Upward