Which theory was revised to obtain the theory of plate tectonics? a continental drift theory b mid-atlantic ridge theory c pangea theory d seafloor spreading theory

In 1912, a German, Alfred Wegener, published his theory that a single continent existed about 300 million years ago. He named this supercontient Pangaea. published this theory of continental drift and claimed that it was supported by several pieces of evidence that these areas were once joined. Wegener's theories were unable to explian how continental movement could have taken place and his ideas gained little ground. From the 1940s onwards, however, evidence began to accumulate to show that Wegener could have been correct. 
The mid-Atlantic ridge was discovered and studied. A similar feature was later discovered in the Pacific Ocean.

question 1

the reasons for the global discontent in the early 1900s were the following:

desire for independence   was the main fight of many territories which were still under the control of colonial powers. dissatisfaction with peace terms of wwi . the best example is the case of germany, that was forced by the peace treaties to pay very expensive war reparations to the winners of wwi. some time later, german leaders broke relations and stopped recognizing the authority of those who imposed sanctions on their country, counting with the support of the population that was suffering the important economic consequences of the payment of reparations. overproduction of consumer goods which led to hyperinflation scenarios and very week currencies and economies.

question 2

the reasons for the great depression were the following, and these led to wall street crash in october 1929 and caused the subsequent great recession period.

high personal debt, that ended up with many bankrupt investors. falling stock price as everybody was getting rid of the stocks, many because they could not meet the amounts of money required by the margins that backed their investments.

question 3

italy: led by the fascists and benito mussolini   and promised to restore the greatness of the roman empire. germany: led by adolph hitler and the nazi party and conducted anti-jewish riots in austriajapan: was controlled by aggressive military leaders and invaded countries for their resources

2.