Baseball brings people together because to win a game the people on the team need to be able to communicate and get along with each, and often time when people are on a team they become friends, which brings them closer. There is no selection, hope this helps though :)
A book was the first ever object that the martian was able to describe. The book was compared to the Caxton. The martian described the Caxton as having a lot of wings and the wings serve as the pages of the book.