Chav Tsev Nyob David Guerra tus tsim qauv qhia txog qhov qhib, ua haujlwm tau zoo, thiab muaj ntau yam sib xyaw ntawm cov ntaub ntawv thiab xim. Cov khoom siv ntuj tsim, xws li ntoo thiab tawv, muaj zog heev nyob hauv qhov chaw, thiab sib piv nrog xim grey tsaus ntawm cov phab ntsa thiab ntau xim sib txawv ntawm daj, ntsuab thiab xiav ntawm cov rooj tog thiab duab kos duab. Cov tswv yim tsim qauv yooj yim, xws li qhov rooj zawm thiab saum npoo sib koom, pab txhawb kev sib koom ua ke ntawm chaw noj mov, chaw nyob, chav ua noj, thiab chaw pw, thaum tseem muab kev ceev npe thaum xav tau.