Read the following (A - D) statements :-
(A) Tight junctions help to stop substances from leaking across a tissue
(B) Adhering junctions perform cementing to keep neighbouring cells together.
(C) The simple epithelium consists of two or more cell layers and has protective function.
(D) The columnar epithelium is made of a single layer of flattened cells with irregular boundaries
How many of the above statements are correct

Options

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

Answer

To determine how many of the statements (A - D) are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A: "Tight junctions help to stop substances from leaking across a tissue."**
- **Analysis:** This statement is true. Tight junctions are specialized connections between adjacent cells that prevent the passage of materials between them, effectively sealing the tissue and preventing leakage.
- **Conclusion:** Statement A is correct.

2. **Statement B: "Adhering junctions perform cementing to keep neighbouring cells together."**
- **Analysis:** This statement is also true. Adhering junctions, also known as desmosomes, are structures that anchor adjacent cells together, providing mechanical stability to tissues.
- **Conclusion:** Statement B is correct.

3. **Statement C: "The simple epithelium consists of two or more cell layers and has protective function."**
- **Analysis:** This statement is false. Simple epithelium is characterized by a single layer of cells, not two or more layers. It can have various functions, including absorption and secretion, but it is not primarily protective, which is more typical of stratified epithelium.
- **Conclusion:** Statement C is incorrect.

4. **Statement D: "The columnar epithelium is made of a single layer of flattened cells with irregular boundaries."**
- **Analysis:** This statement is false. Columnar epithelium consists of a single layer of elongated (not flattened) cells. The description of flattened cells pertains to squamous epithelium, not columnar.
- **Conclusion:** Statement D is incorrect.

### Final Count of Correct Statements:
- Correct Statements: A and B
- Incorrect Statements: C and D

Thus, **2 statements (A and B) are correct.**