Dryness yog ib qho ntawm txoj kev khaws cov ntaub ntawv los ntawm kev lwj.
Muaj ntau txoj hauv kev ua kom qhuav, xws li lub hnub ziab, npau ntub kom qhuav, ziab kom qhuav, kom qhuav, kom qhuav, ziab kom qhuav.
Txawm li cas los xij, cov kev ua kom qhuav no yog nqa tawm ntawm qhov kub ntawm 0 degree lossis siab dua.
Cov khoom uas tau qhuav tau txais, nws yog cov ntim tau muaj feem ntau, cov khoom siv hluav taws xob ua tau zoo, yog tias muaj protein ntau, yog tias cov vitamin tuaj yeem ua rau kev cuam tshuam.
Cov kab mob me me yuav poob kev loj hlob biological, cov khoom siv qhuav tsis yooj yim rau yaj hauv dej thiab lwm yam.
Yog li ntawd, cov khoom ntawm cov khoom qhuav yog qhov sib txawv heev ntawm cov neeg ua ntej ziab.
Txoj kev khov-kom qhuav yog txawv ntawm cov txheej txheem los saum toj no. Cov khoom lag luam yog qhov kub qhuav ntawm qhov kub hauv qab 0 degree, uas yog, nyob rau hauv lub xeev khov khov ntawm cov khoom. Txog rau thaum tom qab theem tom qab, txhawm rau txo cov ntsiab lus noo noo ntawm cov khoom, cov khoom tsis pub muaj qhov kub siab tshaj 40} deg degree, tab sis feem ntau tsis tshaj 40 degree.