How do the words "sever" and "adjoin" relate to each other?

The correct choice highlights that "sever" and "adjoin" express opposing concepts. To sever means to cut off or separate something, while to adjoin signifies the act of joining or being next to something else. Understanding these definitions reveals that they are indeed contradictory, as one action involves breaking a connection (sever), and the other involves creating or maintaining a connection (adjoin). This relationship showcases the contrast in meanings and uses of the terms in language.