Yeah, in case I get hurt during battle, it's important to know those details.

[ Mina tilts her head curiously at the question before she laughs, shaking her head. heck, you already calld her a barbie, Tony ] Ah, I get it, I get it. I don't look like you, right? I'm still human, tho. [ she already knows in other worlds all humans look... well, human. ]

Quirks are genetic. Biology and genes change so the Quirk can manifest, but also so the body can adapt to the quirk - and mine was my melanin. I look like this so my body can withstand my acid without burning myself. I dunno about the horns, but it's because of it too.