[A]: Jaws suspensorium in Mammals is craniostylic.
[R]: Articulation of lower jaw is at the mandibular fossa of the squamous region of the temporal bone rather than at the quadrate.

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 and R is false
D. If both A and R are false

Answer

To solve the question regarding the assertion and reason about the jaw suspensorium in mammals, we can break down the information step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Jaws suspensorium in Mammals is craniostylic."
- **Explanation**: In mammals, the jaw suspensorium is indeed craniostylic, meaning that the upper jaw (maxilla) is directly attached to the skull (cranium). This is a characteristic feature of mammals that differentiates them from other vertebrates.

2. **Understanding the Reason (R)**:
- The reason states that "Articulation of the lower jaw is at the mandibular fossa of the squamous region of the temporal bone rather than at the quadrate."
- **Explanation**: In mammals, the lower jaw (mandible) articulates with the skull at the mandibular fossa, which is part of the squamous region of the temporal bone. This is different from other vertebrates (like reptiles) where the lower jaw articulates with the quadrate bone. This adaptation allows for more complex movements of the jaw, such as chewing.

3. **Evaluating the Truth of A and R**:
- Both the assertion (A) and the reason (R) are true statements.
- The reason (R) provides a valid explanation for the assertion (A) because the craniostylic nature of the jaw in mammals is directly related to the articulation of the lower jaw at the mandibular fossa.

4. **Conclusion**:
- Since both A and R are true and R correctly explains A, the correct answer is that both A and R are true, and R is the correct explanation of A.

### Final Answer:
- Both A and R are true, and R is the correct explanation of A.

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