[Talking about things that are alive and things that are dead, having just toured the local cemetery in an effort to understand what's a big deal (dying, getting a serious disease, moving, having a new baby) and what's a little deal (little brother entering the car through big brother's side, not being first out of the bath, or not being able to play our pinball game 24/7)].
E: Sometimes when you're born with 2 heads, you have to get one cut off because 2 is too many.
Me: Yes, sometimes that happens but it's very rare.
E: Does it happen once every 7 years?
Me: I don't know how often, but it's very rare.
E: Why don't you know about that? You should look it up.