Constant returns to scale exist if ________________ Question 19 options: When a firm increases its plant size and labor employed by the same percentage, its output increases by a smaller percentage and average total cost increases When a firm increases its plant size and labor employed by the same percentage, its output increases by the same percentage and average total cost remains constant. When a firm increases its plant size and labor employed by the same percentage, its output increases by a larger percentage and average total cost decreases. None of the above