Which situation allows for evolution during gene duplication?
a. existing genes are copied over generations.
b. a mutation occurs in one copy of the original gene.
c. the original gene never duplicates.
d. the original gene performs the same role as the mutated gene.

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.