You may be able to like discussion replies in your course.
Note:
In Course Navigation, click the Discussions link.
Click the title of the discussion.
Locate the reply and click the Like icon.
The Like icon will change from gray to blue, indicating you have liked the reply [1].
When a reply is liked, the Like icon will also display the total number of likes for all users in the discussion [2].
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.