Final answer:
The kangaroo rat's efficient kidneys and nocturnal behavior are adaptations that enable it to survive in the water-scarce desert environment.
Step-by-step explanation:
From the fact that the kangaroo rat thrives in the desert, we can infer that it has adaptations suited to arid conditions. The kangaroo rat has very efficient kidneys, which produce concentrated urine, thereby minimizing water loss. This adaptation along with nocturnal behavior, which allows the kangaroo rat to avoid the extreme heat of the day, and possibly other adaptations such as obtaining water through its diet or conserving it through metabolic processes, enables the kangaroo rat to successfully inhabit desert biomes where water is scarce and conditions are harsh.