Answer:
The Treaty of Versailles ended World War I between Germany and the Allied Powers. Because Germany had lost the war, the treaty was very harsh against Germany. Germany was forced to "accept the responsibility" of the war damages suffered by the Allies. The treaty required that Germany pay a huge sum of money called reparations.
Japanese Expansion
In the period before World War II, Japan was growing rapidly. However, as an island nation they did not have the land or the natural resources to sustain their growth. Japan began to look to grow their empire in order to gain new resources. They invaded Manchuria in 1931 and China in 1937.
Fascism
With the economic turmoil left behind by World War 1, some countries were taken over by dictators who formed powerful fascist governments. These dictators wanted to expand their empires and were looking for new lands to conquer. The first fascist government was Italy which was ruled by the dictator Mussolini. Italy invaded and took over Ethiopia in 1935. Adolf Hitler would later emulate Mussolini in his takeover of Germany. Another Fascist government was Spain ruled by the dictator Franco.
These are the only reasons I know. Hope this helps! Stay safe!
It helps create a concerned, yet optimistic tone.
