12. The amount of calendar time associated with the long run ?A. is less than that associated with the immediate market period B. s the same for all firms. C. varies from industry to industry. D. is. by definition, any length of time greater than one year. 13. The law of diminishing returns indicates that: A. as extra units of a variable resource are added to a fixed resource; marginal product will decline beyond some point.B. because of economies and diseconomies of scale a competitive firm's long-run average total cost curve will be U-shaped. C. the demand for goods produced by purely competitive industries is down sloping. D. beyond some point the extra utility derived from additional units of a product will yield the consumer smaller and smaller extra amounts of satisfaction. 14. If a technological advance reduces the amount of variable resources needed to produce any lev el of output, then the:A. AVC curve will shift upward. B. MC curve will shift downward. C. ATC curve will shift upward. D. AFC curve will shift downward. 15 Economies and diseconomies of scale reflect: A. the profit-maximizing level of production. B. why the firm's long-run average total cost curve is U-shaped. C. why the firm's short-run marginal cost curve cuts the short-run average variable cost curve at its minimum point. D. the distinction between fixed and variable costs. 16. The minimum efficient scale of a firm: A. is realized somewhere in the range of diseconomies of scald. B. occurs where marginal product becomes zero. C. is in the middle of the range of constant returns to scale D. is the smallest level of output at which long-run average total cost is minimized. 17. Diseconomies of scale arise primarily because: A. the short-run average total cost curve rises when marginal product is increasing. B. of the difficulties involved in managing and coordinating a large business enterprise. C. firms must be large both absolutely and relative to the market to employ the most efficient productive techniques available. D. beyond some point marginal product declines as additional units of a variable resource (labor) are added to a fixed resource (capital).