For a perfectly competitive a. the marginal revenue curve and the marginal cost curve are the same. b. the supply curve and the marginal revenue curve are the same. c. the demand curve and the marginal cost curve are the same. d. the marginal revenue curve and the demand curve are the same.

i would say their habit of breaking down.

1) the stages a new product goes through from beginning to end, i.e., the stages that a product passes through from introduction through growth, maturity, and decline. 2) the time from initial research and development to the time at which sales and support of the product to customers are withdrawn. 3) the period of time during which a product can be produced and marketed profitably.

                                          hope it