The rest of the vitamin C synthesis machinery may be there, but it's obviously not consuming any energy if it's not producing anything. There's also some specu

The rest of the vitamin C synthesis machinery may be there, but it's obviously not consuming any energy if it's not producing anything. There's also some speculation that eliminating vitamin C synthesis had other beneficial effects, beyond saving energy: https://en.wikipedia.org/wiki/L-gulonolactone_oxidase#Consequences_of_loss https://en.wikipedia.org/wiki/L-gulonolactone_oxidase#Conseq...