Why did usa enter the world war 1?

The U.S. entered World War I because Germany embarked on a deadly gamble. Germany sank many American merchant ships around the British Isles which prompted the American entry into the war.

Explanation:

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.