The kangaroo rat or the dessert rat is one of the common animal found in the arid regions. The animals and the plants which live in the desserts have certain adaptations which enable the organism to survive in the extreme climate. The water which is produced as the product of the metabolic reactions is known as the metabolic water. The kangaroo rat uses the metabolic water which is produced by the reactions in the body rather than the less amount of water which is available in the environment

Answer:

During extreme aridity, Desert Rat uses metabolic water.

Explanation:

During extreme aridity, when water availability is very limited, desert animals have evolved various adaptations to survive in such harsh conditions. One such adaptation is the ability to utilize metabolic water.

Metabolic water:
Metabolic water refers to the water produced as a byproduct of metabolic processes that occur within an organism's body. It is generated during the breakdown of food molecules through cellular respiration.

Adaptations of Desert Rat:
Desert rats, also known as kangaroo rats, are small rodents found in arid regions. They have evolved several physiological and behavioral adaptations to cope with water scarcity. One of these adaptations is the ability to use metabolic water.

Conserving Water:
Desert rats have efficient kidneys that help in conserving water by producing concentrated urine. They also have a low metabolic rate, which reduces the water loss through respiration. Additionally, they have specialized nasal passages that help in minimizing water loss during exhalation.

Utilizing Metabolic Water:
Desert rats obtain a significant portion of their water requirements through metabolic water. When they digest food, the metabolic breakdown of organic molecules (carbohydrates, fats, and proteins) releases water as a byproduct. This metabolic water is then absorbed and utilized by the body.

Minimizing Water Loss:
Desert rats have also evolved physiological adaptations to minimize water loss. They have specialized kidneys that allow them to reabsorb as much water as possible from their urine. They produce highly concentrated urine, which helps in conserving water. Additionally, they have efficient water-conserving mechanisms in their digestive system to extract maximum moisture from their food.

Conclusion:
During extreme aridity, desert rats rely on metabolic water as a crucial source of hydration. This adaptation allows them to survive in the harsh desert environment where water availability is limited. By efficiently utilizing metabolic water and minimizing water loss through various adaptations, desert rats have adapted to thrive in arid conditions.