What year did world war 2 officially start

Hitler started expanding Germany in the early 1930's. This fact gives some people the idea that it actually started then. Japan also broke apart from the united nations in the early 30's after some attacks on China. The actual fighting started September 1st, 1939.

2. a land bridge connected asia and north america thousands of years ago.

4. crossing the land bridge would have been simple for the first migrants.

5. people might have crossed a land bridge while hunting animals.