Yes, it is possible for people to merge topics together on Quora. Topics can be merged together on the /manage subpage of each topic that is accessible in the "..." menu from the topic page.
Two topics should be merged together if the merge satisfies all the policies and guidelines around topic merging.
When you are on the topic manage subpage, there will be a topic search box that will allow you to pick a topic to merge that topic into.
All topic merges are reviewed for accuracy and any mistaken merges will be undone. Most topic merges will happen immediately and be reviewed afterwards. Some topic merges are required to be review before they take place. You will be notified about the outcome of the review afterwards. The most prominent topics on Quora are locked from edits, which includes merges.