(Answered) Whywhy does marginal cost have a U shapeWhywhy does marginal cost have a U shape

➤ Why does the law of diminishing marginal returns make marginal cost rise?
The law implies that after some point each additional worker or input adds less extra output. Firms then use more labor or materials per unit, so variable cost per unit rises. That increases marginal cost in the short run because fixed factors limit how productively inputs combine.