The answer is that it's a pun.
Answer:
a member or advocate of a movement calling for the liberation of people or animals.
Depending on the subject, he could go to his text book, online ebook, etc. He could look at his review if he was given one. He could find other books relating to the subject that could potentially help. (Not much to go on, hope this helps c:)
What is the rest of the question
Answer:
d. feedback messages
Explanation:
A feedback message is a type of message between two speakers whereby one speaker communicates to the second speaker and receives a reply, answer or feedback.
Without feedback, a communication is not complete.