Answer to Question 1
ANSWER: The most recent North American glaciers reached their maximum thickness and extent about 18,000 to 22,000 years ago. At that time, the sea level was perhaps 120 m (395 ft) lower than it is now. The lower sea level exposed vast areas of land, such as the Bering land bridge, a strip of land that connected Siberia to Alaska, which allowed human and animal migration from Asia to North America.
Answer to Question 2
ANSWER: True