When is speciation complete?

Speciation has become complete when organisms of one population do not recognize the mating call of another population and so mating does not occur. Which of the following statements about reproductive barriers and speciation is true? Speciation can occur with even a single gene mutation if that mutation involves reproductive barriers.

Explanation:

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.  

straight or amphibians are homeothermic to thermal