3. What direction did humans have to travel to get from Asia to North America?

Scientists have been pondering two possible routes for decades. One crawls along the Pacific Coast, weaving between the islands of southern Alaska; the other slips between two giant ice sheets, much further east and inland. In order to help figure out how plausible the first route is, a team of scientists wanted to measure how long ago ice sheets retreated from the coastline—and now they've done just that, as they report in a new paper published in the journal Science Advances. The new research suggests the route would have been accessible about 17,000 years ago.

Explanation:

the quote by walter cronkite contributes to the central idea of the text by supporting the central idea. cronkite argues that what is deemed “right” for and in america may not be good for other countries. this supports the central idea of the text, that the vietnam war was unpopular in america for multiple reasons- including cronkite’s.

this is a good question! i'll do some research and come back when i have the answer!