Kev Lag Luam Ntau Lawm
Peb cov khoom tau raug xa tawm mus rau ntau tshaj 50 lub teb chaws thiab cheeb tsam, xws li East Asia, Africa, South America, East Asia thiab lwm yam. Cov neeg siv khoom hauv ntau tshaj 10 lub teb chaws xws li Russia, Ukraine, Ghana, thiab Is Nrias teb yog cov tuam txhab ua lag luam hauv zos.Lub caij no, peb tau teeb tsa cov tuam txhab lag luam sib koom ua lag luam hauv Ghana, Russia, thiab lwm yam kom zoo dua tshawb nrhiav cov khw hauv zos.