I believe that the subjects, between the ones I'm currently studying, that interest me the most are Biology and Geography (the Human part). That said, I will stick with Geography for my Extended Essay as it's a broader subject that gives me various possibilities and I'm really interested in the aspect of it that explores the relationships between humans and the environment they are in, as well as the social patterns seen in socities and how people respond to it.
Moreover, it seems to me that my Geography teacher, Mr. Roberts, would be able to give me advice.