Read the following statements and select the appropriate option :
I. The pliability and flexibility in cartilages are mainly due to the presence of chondroitin salts in its matrix.
II. The hardness of bone is due to calcium phosphate and collagen fibres with ossein protein.
III. The total number of bicephalic ribs in humans are 12 pairs.
IV. The sutures between skull bones are examples of cartilaginous joints.

Options

A. I , III and IV are incorrect
B. II and III are incorrect
C. III and IV are correct
D. I, II, and III are correct

Answer

To solve the question, we will evaluate each statement one by one to determine whether they are true or false.

### Step 1: Evaluate Statement I
**Statement I:** The pliability and flexibility in cartilages are mainly due to the presence of chondroitin salts in its matrix.

- **Analysis:** Chondroitin sulfate is indeed a significant component of cartilage, contributing to its flexibility and pliability. Therefore, this statement is **true**.

### Step 2: Evaluate Statement II
**Statement II:** The hardness of bone is due to calcium phosphate and collagen fibres with ossein protein.

- **Analysis:** Bones are primarily composed of calcium phosphate, which provides hardness, along with collagen fibers that give tensile strength. Ossein is the organic part of bone, primarily made of collagen. Thus, this statement is also **true**.

### Step 3: Evaluate Statement III
**Statement III:** The total number of bicephalic ribs in humans are 12 pairs.

- **Analysis:** Humans have 12 pairs of ribs, which include 7 pairs of true ribs and 5 pairs of false ribs. The term "bicephalic ribs" refers to the structure of the ribs connecting to the vertebrae. Therefore, this statement is **true**.

### Step 4: Evaluate Statement IV
**Statement IV:** The sutures between skull bones are examples of cartilaginous joints.

- **Analysis:** The sutures in the skull are actually examples of fibrous joints, not cartilaginous joints. Therefore, this statement is **false**.

### Conclusion
After evaluating all statements:
- Statement I: True
- Statement II: True
- Statement III: True
- Statement IV: False

Thus, the correct option is that **the first three statements are true, and the fourth statement is false**.

### Final Answer
The correct option is **Option 4** (1st, 3rd, and 4th are incorrect).