What protects clowns from the sun?
A bozone layer.
Alright, listen up, smarty pants! You see, the joke is playin' on words. Instead of "ozone layer," which protects us from the sun, it's "bozone layer." "Bozo" is another word for a clown, so it's like, a layer made of clowns! Get it? Bet you feel real dumb now, huh?