You can reply to the latest parent comment under an item of content, directly in the mobile social feed.
You can like the latest parent comment under an item of content, by clicking the Like icon on the comment. 
To reply to the latest parent comment:
- Tap Reply underneath the parent comment.
The Reply to [User name] field appears. - In the Reply to [User name] field, enter your reply.
- Tap the Send icon.
- Your reply is temporarily posted below the parent comment.
Once posted, your reply is displayed temporarily. If you refresh the feed, it is hidden from view.