Peb yam tseem ceeb ntawm kev kub hnyiab yog: oxygen, lub txim taws, thiab cov khoom sib txuas. Yog tsis muaj ib qho ntawm lawv, kev hlawv yuav tsis tshwm sim. Ntawm qhov hnyav qhov chaw rov qab los, muaj cov pa thiab cov khoom sib txuas ua ke, yog li qhov tsuas tuaj yeem tswj tau yog tias yuav tsum tsis muaj lub txim taws.
Yog li ntawd, lub tshuab rov ua kom hnyav yog tsim los nrog cov txheej txheem pov thawj tawg nyob rau txhua qhov chaw uas yuav muaj lub txim taws. Piv txwv li, lub kaw lus tswj hluav taws xob tau teeb tsa hauv lub thawv kaw qhov tawg tawg, 100% pov thawj tawg, thiab cov cua sov ua kom tawg. Cov cua txias tseem yog qhov pov thawj tawg kom tsis txhob muaj hluav taws xob tawg.
