Kev lag luam khoom siv tes ua suav nrog ntau pawg ntawm cov khoom lag luam, suav nrog cov khoom siv hauv tsev, khoom plig, kho kom zoo nkauj, thiab qee yam khoom yug los ntawm cov koob tsheej tshwj xeeb, xws li cov duab thav duab thiab cov ntawv loj hlob nrog cov menyuam yug los.Tseem muaj kab tshoob kev kos thiab khoom siv tshoob....
Nyeem ntxiv