Read the following statements carefully :
(1) Gap junction facilitates the cells to communicate with each other by connecting the cytoplasm of two adjoining cells to cytoplasm of two adjoining cells .
(2) Adhering junctions help to stop substances from leaking across a tissue .
(3) compound epithelium covers the dry surface of the skin only and provides protection against chemical and mechanical stresses.
(4) most of the bones in vertebrates embryos are replaced by cartilages in adults.
How many of the above statement is/are correct ?

Options

A. Four
B. Three
C. One
D. Two

Answer

To determine how many of the provided statements are correct, we will analyze each statement one by one.

### Step 1: Analyze Statement 1
**Statement:** Gap junction facilitates the cells to communicate with each other by connecting the cytoplasm of two adjoining cells.

**Analysis:** This statement is correct. Gap junctions are specialized intercellular connections that allow direct communication between adjacent cells by connecting their cytoplasms. This enables the transfer of ions and small molecules, facilitating cellular communication.

### Step 2: Analyze Statement 2
**Statement:** Adhering junctions help to stop substances from leaking across a tissue.

**Analysis:** This statement is incorrect. Adhering junctions (or adhesion junctions) primarily provide mechanical stability and support between cells. The junctions that prevent leakage of substances are called occluding junctions or tight junctions.

### Step 3: Analyze Statement 3
**Statement:** Compound epithelium covers the dry surface of the skin only and provides protection against chemical and mechanical stresses.

**Analysis:** This statement is also incorrect. While compound epithelium does cover the dry surface of the skin and provides protection, it is not limited to just this area. It also covers moist surfaces, such as the buccal cavity. Therefore, the statement is misleading as it implies exclusivity.

### Step 4: Analyze Statement 4
**Statement:** Most of the bones in vertebrate embryos are replaced by cartilages in adults.

**Analysis:** This statement is incorrect. In vertebrates, many of the cartilaginous structures formed during embryonic development are replaced by bone through a process called endochondral ossification. Therefore, the statement is not accurate.

### Conclusion
After analyzing all four statements:
- Statement 1 is correct.
- Statements 2, 3, and 4 are incorrect.

Thus, only **one statement** is correct.

### Final Answer
**Only 1 statement is correct.**

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