Hello! I believe the answer is the last one. Supported democratic South Korea against communist backed North Korea. Hope this helps!
Answer:
I think 14 years .........
This letter was written by Leo Szilard, a Hungarian-German-American physicist and signed by Albert Einstein on August 2, 1939. In this letter he urged the president to get involve on a nuclear research and project as Germany might be planning and developing an atomic bomb.
The Bering land bridge is a theory of how early humans migrated to the Americas from Asia about 20,000 years ago.