Kangaroo and desert rat that live in conditions of water scarcity are capable of meeting all their water requirements by

Options

A. having a thick coat to minimise evaporative desiccation
B. oxidising stored fat to produce water as by product
C. producing very concentrated urine and solid faeces
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Environment**: The kangaroo rat and desert rat live in arid conditions where water is scarce. This environment poses a significant challenge for survival, as water is essential for all living organisms.

2. **Adaptation Mechanisms**: To cope with water scarcity, these animals have developed several adaptations. We will explore these adaptations in detail.

3. **Thick Coat**: One of the adaptations is having a thick coat. This thick fur minimizes evaporative water loss (desiccation) from their bodies. By reducing the surface area exposed to the air, they can retain moisture more effectively.

4. **Metabolic Rate Reduction**: The kangaroo rat can slow down its metabolism. A slower metabolic rate means that less water is lost through respiration. This adaptation helps them conserve water, as metabolic processes typically generate water as a by-product.

5. **Oxidizing Stored Fat**: Another key adaptation is the ability to oxidize stored fats. When the kangaroo rat metabolizes its food, particularly seeds, water is produced as a by-product. This means they can meet their water requirements without needing to drink water directly.

6. **Concentrated Urine and Feces**: The kangaroo rat also produces very concentrated urine and solid feces. This adaptation minimizes water loss during excretion. By excreting waste in a concentrated form, they retain as much water as possible.

7. **Conclusion**: All these adaptations allow the kangaroo rat and desert rat to survive in their harsh, dry environments. Therefore, the correct answer to the question is that they meet all their water requirements through these adaptations.

**Final Answer**: D) All of these.

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