does　の役割

In 2010, Cleveland State University researchers found evidence that not only does a person's internal clock start at the moment of birth, but that those born at night might have lifelong challenges performing during daytime hours.

今年の共通テスト第６問Ａの問題なのですが、
１．文中の２つのthat
２．文中のdoes
の役割は何なのでしょうか。