The way Mikumo's smile shifts slightly upwards implies that yes, it should be obvious, but considering most of the significant alien races in her universe are humanoid, she can't entirely blame someone for asking. Windermereans are practically indistinguishable from humans besides their runes, for example.

"Ragnans have fins and gills, so no," she says, rather simply. She's fairly certain some elements of her 'design' were to favour the fact that she mostly lives on Ragna, but she herself isn't a Ragnan. "Does your Earth have any alien contact at all at this point in your timeline?"

It's obvious already that things didn't go down the way they did where Mikumo comes from, but the discussion she had earlier involved someone from the same year as Codi who'd also already had alien contact with their Earth, so it's worth inquiring further.