"What are you passionate about?" The question might not be straightforward to answer, mainly because the word passion is not defined properly.
Passion can be misunderstood to be solely about an activity. For example, I can appear to be passionate about coding, but my real passion is problem solving. Coding just happens to be one outlet. What the world thinks you're passionate about and what you're really passionate about can be worlds apart.
Passion is a lot like taste buds. You like certain kinds of food, and you hate other kinds. There are hundreds of delicacies you've not tasted yet, and you'll have to try them before you're really sure whether you like them or not.
Similarly, your passion can be abstract. It can be a preference toward certain characteristics of activities, rather than the activities themselves. Which is why with time, it's perfectly okay for you to change the activities that you engage in, or the problems that you work on, while still being true to your passion.