Which of the following battles was not only a devastating loss for the United States but also the reason that the United States became involved in world war 2?

Pearl Harbor

Explanation:

Pearl Harbor wasn't really a "battle", more-so it was a surprise attack by the Japanese on US soil. Many American lives were lost, so it is considered a devastation loss. The US decided to join the war against Japan and its allies because of the unprovoked attack.

john maynard keynes developed new economic theories in response to the : b) great depression of the 1930s. his theories are so important that they are known as "keynesianism". in his works he supports the idea of a government with deeper involvement and intervention to end the great depression.

they supported black codes so the answer is a or b