The strength and rigidity of a cell wall is due to the substance known as
A. Suberin
B. Cellulose
C. Lignin
D. Pectin

Hint: A complex organic polymer that is the key structural element in the support tissues of various plants, and fungi. It has an important role in the formation of cells. It is a high molecular weight polymer of phenyl propane derivatives having methoxy side chains. It helps to provide strength and rigidity to the cell wall in various organisms.

Complete answer: In plants and fungi, cell walls are rigid, and the tough outer layer provides structural support and protection to the cells. Several components of cell walls such as cellulose and lignin provide strength and rigidity. Cellulose is a carbohydrate that is the strongest component of the cell wall. While lignin forms an additional layer on the primary cell wall and helps in increasing the cell wall rigidity and also helps in maintaining its structure. The permanent plant tissues contain lignin.

Hence, the correct option is C-Lignin.

Note: Lignin is a vital structural polymer present in the cell wall of certain cells and helps in regulating various functions such as transport, support, and resistance to different stresses. It is present in the secondary cell wall not in the primary cell wall. It is a structural polymer that maintains the structure of the cell wall and prevents the cell wall from damage and attack of various microorganisms. It is commonly found in the permanent tissues.