But the most valid response is simple.
Chemistry is the study of how matter behaves.
We have only one world in which to live. If we want to know how we can change it and what we cannot alter, or even simply to appreciate what we already have, then we must know how it works. Chemistry is the subject that tells us this. Physics may teach us fundamental facts about elementary particles, matter, and energy, but it stops short of drawing conclusions about how the different kinds of matter around us change and react. Biology describes the large-scale behavior of organisms, which at their core are elaborate chemical systems.