Your world's better off for that. Mako was produced from the spirit energy of the Planet. Most people didn't realize, but the Planet was slowly dying. It's fine now, though. Healing.

[ It's humanity that's in trouble. ...In fact, her world's probably healthy enough to not have the similarity he'd be most interested in. ] On your world--have people ever dealt with a disease called 'Geostigma'?

[ It's a cosmically long shot. Literally on the "cosmic" part. But...if the worlds are similar at all, he can't not ask. ]