Peb lub hnab npuas yog qhov kev xaiv zoo tshaj plaws rau cov khoom tawg yooj yim lossis cov khoom ntiag tug thiab cov khoom lag luam. Muaj ntau yam kev siv, xws li xa cov khoom tseem ceeb xws li xov tooj ntawm tes, ntim cov khoom uas tsis yooj yim xws li tsom iav. Tsis tas li, nws tuaj yeem siv los khaws cov khoom zoo, vim nws yog dej tsis nyab thiab poob pov thawj. Cov hnab ua npuas muaj qhov siab dua kev sib tw thiab lub teeb yuag, yog li tsis muaj kev ntseeg tias lawv tuaj yeem khaws koj cov khoom kom zoo thiab nyab xeeb thaum txuag tus nqi thauj.
