The cell structure present in collenchyma but absent in sclerenchyma is

Options

A. Lignified cell walls
B. Unevenly thicked cell walls
C. Vacuoles
D. Pits in cell wall

Answer

To answer the question, "The cell structure present in collenchyma but absent in sclerenchyma is," we will analyze the characteristics of both collenchyma and sclerenchyma.

### Step-by-Step Solution:

1. **Understand Collenchyma**:
- Collenchyma is a type of plant tissue that provides support while allowing for growth.
- The cells in collenchyma are living and have elongated shapes.
- The cell walls of collenchyma are thickened, but importantly, they are **unevenly thickened**. This means that the thickness of the cell walls varies from one part of the cell to another.

2. **Understand Sclerenchyma**:
- Sclerenchyma is another type of supporting tissue in plants, but it is made up of dead cells.
- The cells in sclerenchyma are usually more rigid and woody due to their heavily thickened secondary walls.
- The thickening in sclerenchyma is **even**, meaning that the cell walls have a uniform thickness throughout.

3. **Compare the Two Tissues**:
- The key difference between collenchyma and sclerenchyma is in the thickness of their cell walls.
- Collenchyma has **unevenly thickened cell walls**, while sclerenchyma has **evenly thickened cell walls**.

4. **Identify the Correct Answer**:
- Given the options:
- Lignified cell walls
- Unevenly thickened cell walls
- Vacuoles
- Pits in cell walls
- The correct answer is **unevenly thickened cell walls**, as this feature is present in collenchyma but absent in sclerenchyma.

### Final Answer:
The cell structure present in collenchyma but absent in sclerenchyma is **unevenly thickened cell walls**.