Answer:
2 I am sorry If it is wrong
Answer:
A President Truman learned of the success of the Manhattan Project
Explanation:
American President Harry Truman made the decision to use the devastating atomic bomb on Japan as a direct response to the Pear Harbor attack on American soil.
The direct result of this was that the Japanese gave their unconditional surrender and the war was ended.
However, the indirect result of the decision to drop the atomic bomb was that President Truman learned of the success of the Manhattan project which was the atomic bomb.
The American attitude shifted in favor of rights for Native Americans. This is based on "Polls showed that Americans believed in rights for Native Americans". Why it's not A is because it wasn't the polling that contributed to the act, but what the polls showed which is C.