Why?

Corbin is THOROUGHLY in his "why" phase. Sometimes I wonder if he's just doing it to be snarky and not because he's actually curious, because surely he doesn't understand everything he's asking.

An example from this morning (one of literally at least 10 similar conversations we've had so far today, and it's not even 9 am):
"Cereal all gone?"
"yup"
"Why?"
"Because I ate it all"
"Why?"
"Because I like it and I eat it every morning"
"Why?"
"Because I have to eat something every morning"
"Why?"
"Because I need fuel for my body to get through the day"
"Why?"
"Because your body needs energy to work right, and we get that from food. We eat the food, and then our body turns it into sugar and usable things and that makes our muscles move and our brains work and fixes our cells."

Usually by the time I get to the in-depth scientific explanations he loses interest and moves on to the next string of "why"s.