Skeleton is made entirely of cartilage in

Options

A. sharks
B. tuna
C. rohu
D. None of these

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which type of fish has a skeleton made entirely of cartilage.

2. **Identify Types of Fish**: There are two main categories of fish based on their skeletal structure:
- Bony fish (Osteichthyes) which have skeletons made primarily of bone.
- Cartilaginous fish (Chondrichthyes) which have skeletons made entirely of cartilage.

3. **Recognize Cartilaginous Fish**: Cartilaginous fish include species such as sharks, rays, and skates. These fish do not have bones; instead, their skeletons are made of cartilage, which is a flexible and lighter material.

4. **Examples of Cartilaginous Fish**: Some examples of cartilaginous fish are:
- Shark
- Dogfish
- Stingray
- Torpedo

5. **Examine the Options**: If the options given include a shark, it is important to note that sharks are a prime example of cartilaginous fish. Other options like tuna and rohu are bony fish, as they have a skeleton made of both cartilage and bone.

6. **Conclusion**: Based on the information, the correct answer to the question is that the skeleton made entirely of cartilage is found in sharks.

**Final Answer**: The skeleton is made entirely of cartilage in sharks (option 1).

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