Yep, Trent's a college freshman, like Dean. I wouldn't say it requires Joe to be a real genius (
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) in order to do a little Science 101 homework (after all, he's only a few months away from being a college boy himself), but he's certainly ahead of the curve, at least when it comes to science.
As for Grandma McCarthy, I'll just say that she's a bit eccentric and can be quite matter-of-fact and aloof, but she doesn't have malicious intent.