An answer song is a kind of song that is written in response to another song. It's like when someone asks you a question, and you answer them back. In the music world, sometimes a singer or a songwriter will create a song about a particular topic or situation. Then, someone else will write another song that talks about the same thing, but it has a different perspective or point of view.
For example, maybe there is a popular song called "I Love You". Another singer might create an answer song called "I Know You Love Me Too". This song is responding to the first song and saying that the feeling is mutual.
Answer songs can be a way for artists to express their own opinions or viewpoints on a topic that's already popular. It's also a way to keep a conversation going and keep the music interesting. So, the next time you hear a song that you really like, keep an ear out for any answer songs that might come afterwards!