This is not true of sharks

Options

A. They are as long as 12 m
B. They are viviparous
C. They have swim bladder
D. Their liver is rich source of vitamin A.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which statement is NOT true about sharks. We need to analyze each option provided to determine which one is incorrect.

2. **Reviewing the Options**:
- **Option A**: They are as long as 12 meters.
- **Option B**: They are viviparous.
- **Option C**: They have a swim bladder.
- **Option D**: Their liver is a rich source of vitamin A.

3. **Analyzing Each Option**:
- **Option A**: Sharks can indeed grow as long as 12 meters. For example, the whale shark is known to reach this length. This statement is TRUE.
- **Option B**: Some species of sharks are viviparous, meaning they give birth to live young rather than laying eggs. This statement is TRUE.
- **Option C**: Sharks do NOT have a swim bladder. Instead, they rely on their large liver filled with oil for buoyancy. This statement is NOT TRUE.
- **Option D**: The liver of sharks is known to be a rich source of vitamin A. This statement is TRUE.

4. **Conclusion**: The statement that is NOT true about sharks is that they have a swim bladder. Therefore, the correct answer is **Option C**.

### Final Answer:
**They have a swim bladder.**

---