While looking at What abilities are moderators given? I noticed that the question has been merged:
What is the difference between a merged question, and one that has been closed as a duplicate?
If you look at the text of a Closed as Duplicate post (example) it says:
When questions are merged the answers from both questions are placed into the original question. This will be handy when someone provides a good answer to a duplicate question. After a merge there will only be one question with all the answers, thus making it easier to search and get answers. Also, the answers won't be part of a closed question any more.