The effort from the US, UK and Canada to develop nuclear weapons was known as the Manhattan Project.
The correct answer is her wild and turbulent past.
When she was very young she contracted polio. She had a limp and her father wanted her to compensate and overcome her limitation by playing sports. She also was seriously injured in a traffic accident and damaged her hip. It was during the recovery from this accident that she painted her first self-portrait.
Germany's growing power and Britain's desperate need is the correct answer.
The US initially tried to remain neutral during World War II owning to large causalities in World War I. But The Germany's growing power and Britain's desperate need made it increasingly difficult for President Roosevelt to stay neutral. The Germany under Hitler was gaining more and more control in Europe which was being effectively helped by Soviet Union and on the other hand the fall of France had made Britain alone to fight the Axis. So it made difficult for Roosevelt to remain neutral during the World War II.
The Japanese saw it as a great triumph. They traveled to the harbor knowing they can't come back, but knew their people would see them as heros. They saw the US as lazy and terrible people. An easy target. Their attack did devastate many, and hardly any there stood up to the Japanese. Almost proving their views on us.
But by seeing how they did that and thought we were "lazy" we just sent a nuke there and made them see us differently ;)