Why do bacteria thrive even in hostile environments

Due to their high adaptability

Explanation:

Bacteria have high mutations rates hence they increase their chances of having a sub-population that can adapts to an extreme environment they have been introduced to. Forthwith their genes can passed on to bacteria generations both vertically and horizontally. Bacteria also share their genes through horizontal transfer (conjugation) hence advantageous genes can be passed rapidly to the rest of the population in one generation.

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.