1. The long-run average total cost curve is: i) Steeper than the short-run average total cost curve as the firm incurs more fixed costs in the long run. ii) Never steeper than short-run average total cost curves, as the firm can always choose the same input combinations as the short-run. iii) Steeper or flatter than the short-run average cost curve, but it depends on the long-run marginal cost curve. iv) We cannot say without more detailed information on the firm's costs