Where does my “Pee” Come from?

Ubit started his Home Education by discussing about himself.  We decide to explore something really ours, our own body. After a short discussion, he suddenly asked permission to go the bathroom. He wanna pee. This young boy was curious, where his “pee” came from.  My Body has several cartoon movies that help us understand this bathroom stuff. He then ask many questions about “pee” and “poo” and I answer them by clicking the menus. He may merely enjoy the movie rather than the explanations. But it counts.