"What are your favorite courses, and why?" can mean the units of study that you like or in a restaurant which food courses you prefer. I'm guessing that your question refers to university courses. Right? If this is so you could say;
I am fascinated by World History and Geography because I like to see how others see the world and its history. The topics are quite different and interesting. And of course I like languages. I can speak 3 languages (Mandarin, English, French) and in addition I am studying Spanish.