Alcoa had a monopoly in the u. s. aluminum market from the late nineteenth century until the end of world war ii. which barrier to entry was the source of alcoa's monopoly power?

Consider the events in alfred wegener's life that led to his development of the continental drift hypothesis. review the items below and determine whether each item is (1) an observation that led alfred wegener to develop his continental drift hypothesis, or (2) evidence wegener gathered to support his proposal.