Cov khob yas degradable tuaj yeem decomposed nyob rau hauv tej yam kev mob, txo cov pa phem ib puag ncig thiab ua raws li ib puag ncig kev paub.Nyob rau tib lub sijhawm, lawv kuj muaj cov yam ntxwv ua haujlwm ntawm lub khob yas, uas yooj yim, siv tau, lub teeb, thiab nqa tau yooj yim.