Lub luag haujlwm tseem ceeb ntawm cov hniav hauv cov tshuab luam ntawv thiab cov tshuab luam ntawv yog kev ntxuav. Qhov zoo ntawm cov hniav feem ntau nyob ntawm nws cov khoom siv, uas yuav tsum tiv taus qhov kub siab. Feem ntau, cov hniav yuav maj mam puas tom qab ib lub sijhawm thiab yuav tsum tau hloov tsis tu ncua. Yog tias cov hniav puas hnyav heev, cov hniav yuav tsum tau tshem tawm thiab hloov nrog ib qho tshiab.
