7. Why was (and still is) the cinema (aka, movies) the cultural or commercial product with which the United States was (and still is) most closely identified?
8. What did Keynes think was the cause of the Great Depression or any depression/recession, and thus what should the government do to stimulate the economy during these times ?

The cinema is the cultural or commercial product associated with the United States because of the high output quality and the media marketing machine behind the industry.

The Great depression was also referred to as Economic depression and Keynes believed that this was caused by a fall in total demand.

He also said that the government must increase spending in other to stimulate the economy during this period.

Read more about Great depression here