Antidiuretic hormone has the most abundant receptors in the kidneys of

Options

A. frogs in tropical pond
B. rabbits in a grass land
C. spotted deer in moist evergreen forest.
D. Kangaroo rats in deserts

Answer

**Step-by-Step Solution:**

1. **Understanding Antidiuretic Hormone (ADH):**
- Antidiuretic hormone, also known as vasopressin, plays a crucial role in regulating water balance in the body. It helps to prevent excessive loss of water by promoting water reabsorption in the kidneys.

2. **Analyzing the Options:**
- The question provides four options: frogs in tropical ponds, rabbits in grasslands, spotted deer in moist evergreen forests, and kangaroos or rats in the desert. We need to determine which of these animals has the most abundant receptors for ADH in their kidneys.

3. **Evaluating Frogs in Tropical Ponds:**
- Frogs living in tropical ponds have easy access to water. Therefore, they do not need to conserve water, and as a result, they are less likely to have a high concentration of ADH receptors.

4. **Evaluating Rabbits in Grasslands:**
- Rabbits primarily feed on grass, which contains a significant amount of water. Similar to frogs, they do not face water scarcity, so they would not require high levels of ADH or its receptors.

5. **Evaluating Spotted Deer in Moist Evergreen Forests:**
- Spotted deer inhabit moist evergreen forests that receive plenty of rainfall. They also do not experience water scarcity, indicating that they would not have a high abundance of ADH receptors.

6. **Evaluating Kangaroos and Rats in the Desert:**
- In contrast, kangaroos and rats living in desert environments face conditions of dehydration due to high temperatures and limited water availability. To cope with this, their bodies release more ADH, leading to a higher abundance of ADH receptors in their kidneys to facilitate water reabsorption and prevent dehydration.

7. **Conclusion:**
- Based on the analysis, the correct answer is that antidiuretic hormone has the most abundant receptors in the kidneys of kangaroos and rats in the desert.

**Final Answer:** Kangaroos and rats in the desert.

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