Assertion. Tubular secretion alone accounts for excretion in the desert amphibians.
Reason. Desert amphibians have abundant Bowman's capsules and glomeruli.

Options

A. If both A and R are true and R is the correct explanation of A.
B. If both A and R are true but R is not the correct explanation of A.
C. If A is true but R is false.
D. If both A and R are false.

Answer

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "tubular secretion alone accounts for excretion in desert amphibians."
- This means that in desert amphibians, the process of excreting waste primarily occurs through tubular secretion rather than through filtration.

2. **Understanding the Reason**:
- The reason given is "desert amphibians have abundant Bowman's capsules and glomeruli."
- Bowman's capsules are part of the nephron where filtration of blood occurs, and glomeruli are the network of capillaries within the Bowman's capsule that facilitate this filtration.

3. **Analyzing the Relationship**:
- Desert amphibians are adapted to conserve water due to their arid environment. They have specialized nephron types that minimize water loss.
- Typically, desert amphibians possess fewer glomeruli and rely more on tubular secretion rather than filtration for excretion, which contradicts the reason provided.

4. **Conclusion**:
- The assertion is true because tubular secretion does play a significant role in excretion for desert amphibians.
- The reason is false because desert amphibians do not have an abundance of Bowman's capsules and glomeruli; instead, they have adaptations that reduce their number to conserve water.

5. **Final Answer**:
- The assertion is true, but the reason is false.