The Unites states entered a time of prosperity, what two things caused that

A. The mainland was not badly damaged and the war industries were turned into production sites for the production of goods for the increasing population.

B. Advancement in technology  and increase in consumer's spending.

Explanation:

This period was the post WW II era in the 1950's, It was a period that brought about the speedy growth in the economy prosperity of the U.S.  This was due to the low damaged the war caused on the country and the bad damage that was done to other super powers of the world who were the major supplier of goods before the war.

Moreover, there was massive growth in the population which resulted into high demand for goods there by  leading into massive production wish in return lead to an economy boom  because the war industries were turned into production sites to produce goods.

It was a period that was tagged "BABY BOOM" where the economy grew by 37%  and brought about high spending by consumer due to availability of jobs that resulted into high wages.