Vertebrates are also called craniates as the brain is protected by the brain box . In humans the number of bones that from this brain box is

Options

A. 4 paired and 2 unpaired bones
B. 2 paired and 4 unpaired bones
C. 3 paired and 2 unpaired bones
D. 4 paired bones

Answer

To solve the question regarding the number of bones that form the brain box (skull) in humans, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question states that vertebrates are also called craniates because their brain is protected by a structure known as the brain box or skull. We need to determine how many bones make up this structure in humans.

2. **Identifying the Bones of the Skull**:
- The human skull is composed of cranial bones that protect the brain. There are a total of 8 cranial bones in the human skull.

3. **Classifying the Cranial Bones**:
- The cranial bones can be classified into paired and unpaired bones:
- **Paired Bones**: These are bones that come in pairs, meaning there are two of each.
- Parietal bones (2)
- Temporal bones (2)
- **Unpaired Bones**: These are bones that are singular in the skull.
- Frontal bone (1)
- Occipital bone (1)
- Sphenoid bone (1)
- Ethmoid bone (1)

4. **Counting the Bones**:
- From the classification:
- Total paired bones = 2 (Parietal) + 2 (Temporal) = 4 paired bones
- Total unpaired bones = 1 (Frontal) + 1 (Occipital) + 1 (Sphenoid) + 1 (Ethmoid) = 4 unpaired bones
- Therefore, the total number of cranial bones is 4 paired + 4 unpaired = 8 cranial bones.

5. **Choosing the Correct Option**:
- The options provided were:
1. 4 paired and 2 unpaired bones
2. 2 paired and 4 unpaired bones
3. 3 paired and 2 unpaired bones
4. 4 unpaired bones
- Based on our count, the correct classification is 4 paired and 4 unpaired bones, which does not match any option directly. However, the closest option that reflects the number of unpaired bones is option 2, which mentions 2 paired and 4 unpaired bones, but this is incorrect as we have established there are 4 paired bones.

6. **Conclusion**:
- The correct answer is that there are 8 cranial bones in total, with 4 paired and 4 unpaired. However, since the question asks for the number of bones forming the brain box, the answer should reflect the total number of cranial bones, which is 8.