>>280916592Yoko is the one sitting at a desk and making sure their library doesn't get eaten by mildew.
Nagi is out there doing the fieldwork, hiking in the mountains, lugging gear, and carrying mineral samples back.
Sure there's a bit of fat on her body(fat tits notwithstanding), but everything you're seeing is muscle.
If this were an even more sexualized series, there would be a beach episode where she crushes a watermelon with her thighs.