Who proposed that all of the present continents were once joined together in a single supercontinent called Pangaea? Select one: a. Alfred Wegener b. Charles Darwin c. Arthur Holmes d. Harry Hess

Alfred Wegener

Explanation:

In 1915, Alfred Wegener, a German geophysicist and meteorologist first developed the concept Pangea. He proposed that the present continents were once fully assembled together about 175 million years ago before it began to break apart. It is believed that a supercontinent existed during the late Paleozoic and early Mesozoic eras. It is also believed that the formation and breakage of the supercontinent have been cyclical through Earth's history.