The nature of all the 31 pairs of spinal nerves is

Options

A. Sensory
B. Afferent
C. Mixed
D. Motor

Answer

### Step-by-Step Solution:

1. **Understanding Spinal Nerves**:
- The human body has a total of 31 pairs of spinal nerves. These nerves are crucial for transmitting signals between the spinal cord and the rest of the body.

2. **Classification of Spinal Nerves**:
- The 31 pairs of spinal nerves are classified into different regions:
- 8 Cervical pairs
- 12 Thoracic pairs
- 5 Lumbar pairs
- 5 Sacral pairs
- 1 Coccygeal pair

3. **Connection to the Spinal Cord**:
- Each pair of spinal nerves connects to the spinal cord, which is part of the central nervous system. This connection allows for communication between the brain and peripheral body parts.

4. **Nature of Spinal Nerves**:
- Spinal nerves can be classified based on their function:
- **Sensory Nerves (Afferent)**: These nerves carry sensory information from the body to the spinal cord.
- **Motor Nerves (Efferent)**: These nerves carry motor commands from the spinal cord to the muscles.
- **Mixed Nerves**: Most spinal nerves are mixed, meaning they contain both sensory and motor fibers.

5. **Conclusion**:
- Since the question asks about the nature of all 31 pairs of spinal nerves, it is important to note that while some pairs may be purely sensory or motor, the majority are mixed. Therefore, when considering all 31 pairs together, they are classified as having a mixed nature.

### Final Answer:
The nature of all the 31 pairs of spinal nerves is **mixed**.

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