Explain the relationship between a firm's short run production function and its short run cost function. Focus on the marginal product of an input and the marginal cost of production.

"If it were not for the law of diminishing returns, a firm's average cost and average variable cost would not increase in the short run." Do you agree with this statement? Explain.

Explain the difference between a short-run and long-run production function. Cite one example of this difference in a business situation.