D Question 9 The marginal cost curve: Always starts at zero, curves upward, then reverses and curves back downward to zero. Always intersects the average variable and average total cost curves at their minimum points. Always crosses the X axis at some point, regardless of quantity produced. Always crosses the Average Fixed Cost (AFC) curve at its minimum point. D Question 10 A firm produces 300 products with 50 workers and 20 machines. When it doubles its in 100 workers and 40 machines, production more than doubles to 700 products. This is an