What did the world's scientific community discover in 1939? why was this a concern?

Early in 1939, the world's scientific community discovered that German physicists had learned the secrets of splitting a uranium atom. Fears soon spread over the possibility of Nazi scientists utilizing that energy to produce a bomb capable of unspeakable destruction.

Scientists ALBERT EINSTEIN, who fled Nazi persecution, and ENRICO FERMI, who escaped Fascist Italy, were now living in the United States.

b)

it created free trade throughout the colonial territories.

during the ming dynasty