ium ▁ple ist oc enium , ▁as ▁well ▁as ▁Ch ry se ob acter ium ▁green land ensis ▁and ▁Herm ini imon as ▁g lac iei , ▁have ▁reported ly ▁been ▁rev ived ▁after ▁surv iving ▁for ▁thousands ▁of ▁years ▁fro zen ▁in ▁ice . ▁ ▁Pl ants ▁Many ▁plants ▁under go ▁a ▁process ▁called ▁hard ening , ▁which ▁allows ▁them ▁to ▁surv ive ▁temper atures ▁below ▁ 0   ° C ▁for ▁weeks ▁to ▁months . ▁ ▁Anim als ▁The ▁n emat ode ▁Ha emon chus ▁cont ort us ▁can ▁surv ive ▁ 4 4 ▁weeks ▁fro zen ▁at ▁liquid ▁nit ro gen ▁temper atures . ▁Other ▁n emat odes ▁that ▁surv ive ▁at ▁temper atures ▁below ▁ 0   ° C ▁include ▁Tr ich ost rong yl us ▁col ub r iform is ▁and ▁Pan ag ro laim us ▁dav idi . ▁Many ▁species ▁of ▁re pt iles ▁and ▁am ph ib ians ▁surv ive ▁free zing . ▁ ▁See ▁cry obi ology ▁for ▁a ▁full ▁discussion . ▁ ▁Human ▁gam etes ▁and ▁ 2 -, ▁ 4 - ▁and ▁ 8 - cell ▁emb ry os ▁can ▁surv ive ▁free zing ▁and ▁are ▁vi able ▁for ▁up ▁to ▁ 1 0 ▁years , ▁a ▁process ▁known ▁as ▁cry op res ervation . ▁ ▁Ex perimental ▁attempts ▁to ▁free ze ▁human ▁be ings ▁for ▁later ▁rev ival ▁are ▁known ▁as ▁cry on ics . ▁ ▁Food ▁pres ervation ▁ ▁Free zing ▁is ▁a ▁common ▁method ▁of ▁food ▁pres ervation ▁that ▁slow