Collenchyma is a type of simple permanent tissue which provides mechanical strength to plants and consists of living cells. It makes the plant soft at some places and allows in easy bending of the parts of the plant .It is present in tendrils of plants.

The Correct Answer:
The correct answer is option 'C' - collenchyma.

Explanation:
Plant tissues are classified into three main types: meristematic tissue, permanent tissue, and secretory tissue. Permanent tissues are further classified into simple permanent tissue and complex permanent tissue. Collenchyma is a type of simple permanent tissue.

Collenchyma:
Collenchyma is a type of plant tissue that provides mechanical strength and support to the plant. It consists of living cells with thickened cell walls. Collenchyma cells are elongated and have irregularly thickened corners. The thickened cell walls are due to the deposition of cellulose, hemicellulose, and pectin. This provides strength and flexibility to the cells.

Characteristics of Collenchyma:
1. Living Cells: Collenchyma cells are living cells, unlike sclerenchyma cells which are dead at maturity.
2. Elongated Shape: Collenchyma cells are elongated, with their length being greater than their width.
3. Thickened Cell Walls: The cell walls of collenchyma cells are thickened at the corners, providing mechanical strength.
4. Intercellular Spaces: Collenchyma cells have intercellular spaces between them, allowing for gaseous exchange and flexibility.

Functions of Collenchyma:
1. Mechanical Support: Collenchyma provides mechanical support to the plant organs, such as stems, leaves, and petioles. The thickened cell walls and flexible nature of collenchyma cells help in resisting bending and stretching forces.
2. Growth and Flexibility: Collenchyma cells can stretch and elongate as the plant grows, allowing for flexibility and accommodating growth.
3. Protection: Collenchyma cells can also provide protection to the delicate and growing parts of the plant.
4. Gaseous Exchange: The intercellular spaces in collenchyma cells allow for gaseous exchange between the cells and the external environment.

Examples of Collenchyma:
Collenchyma tissue is commonly found in the stems, petioles, and leaf veins of plants. It is also present in the hypodermis (outer layer) of herbaceous plants.

In conclusion, collenchyma is a type of plant tissue that provides mechanical strength and consists of living cells. It has thickened cell walls and allows for flexibility and growth in plants.