Is always a action verb or a linking verb

Whatever crawls in is trapped. is the noun clause - whatever crawls? is the function of the noun clause the subject of the verb trapped?

In chapter 3 of franz kafka’s the metamorphosis, gregor is confined to his room after an injury inhibits his movement. however, he finds solace in being able to hear his family’s conversations through his open bedroom door. what does this detail show about gregor’s state of mind? a. he still feels the need for human company. b. he feels trapped in his house with his family. c. he misses interacting with his kind, loving mother. d. he’s bored and wants to go back to work.

What is a rhythm? (i really forgot )