You may be able to like discussion replies in your course.
Note: The liking feature may be restricted to users with grading permissions (e.g. instructors and TAs). If you cannot like a discussion reply, this feature is not available to you.
Like Discussion Reply
Locate the reply and click the Like icon.
View Liking Restriction
If your instructor has restricted the liking option to only users with grading permissions, you will not be able to see the Like icon or like your favorite replies. However, you can still see the total number of likes given to each reply.