Yog tias qhov xoob ntawm cov hniav yog cov kaus hniav me thiab cov kaus hniav ib sab yog qhov muaj kev noj qab nyob zoo thiab ruaj khov, yog ib qho kev xaiv ruaj khov. Tus hniav ua kom ruaj khov kho cov zom zom ua haujlwm los ntawm kev sib txuas cov hniav xoob rau ntawm cov hniav ntawm ob sab.
NCO TSEG: Cov hniav cuav hniav kom ruaj ntseg yuav tsum tau hnav thiab cov kua muag ntawm ob sab ntawm cov hniav, uas tuaj yeem ua rau cov hniav, yog li tus yam ntxwv xav tau thaum xaiv ib qho.