Well, I’m certain cockroaches can’t learn calculus. Neither can apes or monkeys. Some humans can. Therefore I think that brain composition has something to do with learning calculus. There is variation in said brain composition amongst humans. It seems reasonable to think that the set of all people is not a subset of all things that can learn calculus.
I haven’t performed any genetics tests but brain composition is partly determined by genetics so genetics might play role, right?
You sequenced the genomes of your students and correlated their performance against their genes?