Statement (A): Desert lizards lack physiological ability that mammals have, to deal with high temperature of their habitat. 

Statement (B): Kangaroo rat has the ability to concentrate its urine.

Desert lizards manage to keep their body temperature constant by behavioral adaptation. They bask in sun and absorb heat when their body temperature drops but move into shades when ambient temperature starts increasing.

In the absence of an external source of water, the kangaroo rat in North American deserts is capable of meeting all its water requirements through its internal fat oxidation (in which water is a by product). It also has the ability to concentrate its urine so that minimal volume of water is used to remove excretory products.