A firm's are costs that increase as quantity produced increases. These costs often show illustrated by the increasingly steeper slope of the total cost curve. fixed costs; technological changes variable costs; diminishing marginal returns variable costs; constant returns to scale fixed costs; opportunity costs A firm's are costs that are incurred even if there is no output. In the short run, these costs as production increases. variable costs; do not change variable costs; increase fixed costs; increase fixed costs; do not change