Hi @Jennifer O10. Recently we added a feature that allows you to filter the feeds based on the "Recent Post" or "Recent Activity". Now, on home feed, group page feed, and topic page feed you are able to filter the feed based on the recent activity, so that the post with activities on them (comment, reply, edit, like) will get displayed on top.
You as an admin are bale to define what is the feed sorting default setting. You can make changes from Admin Panel> Settings> Feed> Default Feed Sorting> Save changes.