The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The industries that grew because of the war effort were the large industries that had the resources to produce military vehicles such as cars, jeeps, tanks, and other kinds of weaponry that had to be sent to the war front.
What they had to do to produce weapons was to change and adapt their operation lines in a very short time -we can say a record time. in order to fabricate those military vehicles and weaponry.
For instance, the United States lend-lease program of 1939 helped the Allies in that it gave them war supplies. France and Gretad Britain were the countries that benefited the most from this US legislation.
After Japan's Pearl Harbor attack in December 1941, President Roosevelt asked Congress for a declaration of war against Germany. That is how the US entered World War II.
