1. Why would the U. S. still allow teachers, students, and tourists from China if it viewed Chinese immigrants
as a threat? What potential benefits did these people
bring?

It's not that US hates Chinese people or something it's between governments. Although, US government doesn't hesitate with Chinese people but some Americans tent to dislike them.

b: the establishment clause  

b: socialism  

wisdom

explanation:

the fact that that the teachings on the cosmic order comes from, or through, the heart center