Final answer:
True, heavy industries like aluminum and steel typically show declining long-run average total costs due to economies of scale, which means lower cost per unit with increased production, until diseconomies of scale increase the costs.
Step-by-step explanation:
True, heavy industries such as aluminum and steel typically exhibit a pattern of declining long-run average total costs as they expand and increase production levels. This occurs due to the presence of economies of scale, which means that as production increases, the cost per unit of output decreases, up to a certain point. The reason for this is that fixed costs are spread over more units of output, and operational efficiencies are achieved when operating on a larger scale.
However, this trend of decreasing average costs will not continue indefinitely; after reaching an optimal level of production, further expansion can lead to diseconomies of scale, as the management becomes more complex and less efficient, increasing the average costs. This can be observed in the long-run average cost curve, where the portion showing an increase in average cost is the result of diseconomies of scale.