What about the cooling systems of the naturally occuring nuclear reactors? Is the necessity of cooling non-designed?
When you say "necessity", I think it's important to note that it's necessary as a condition of its existence, in the sense that, in its absence, the thing itself wouldn't really exist. But I don't see how anyone can move from "X is a necessary, if not sufficient pre-condition for Y" to "Y is therefore designed". If silicon didn't exist, sand wouldn't exist - the existence of silicon is necessary for the existence of sand, but does that mean that sand is designed? The existence of water is necessary for the existence of snow - is snow designed? The existence of cooling systems is necessary for the existence of natural nuclear reactors - are natural nuclear reactors therefore designed?
Don't see how B follows from A. The existence of virtually everything is predicated on the existence of some other thing - is everything therefore designed?