By what land bridge did some ancient people migrate to north america, and how was it created? ✨

The first humans to populate America are thought to have migrated from Asia, trough the Bering Straits during the last glacial era. The planet's temperature lowered to 1.5 to 5.5 °F in average, causing water from oceans, lakes, rivers to froze; as the oceans froze, the sea level between Asia and America lowered, allowing people (and animals) to cross from one continent to the other.

which statement explains one of the reasons world war 1 was so much more destructive than earlier conflicts