AP BIOLOGY

Detailed explanation-1: -Sclerenchyma tissue, when mature, is composed of dead cells that have heavily thickened walls containing lignin and a high cellulose content (60%–80%), and serves the function of providing structural support in plants. Sclerenchyma cells possess two types of cell walls: primary and secondary walls.

Detailed explanation-2: -So the correct answer is ‘Woody tissue/Xylem cells. ‘

Detailed explanation-3: -Lignin is a component of the cell walls of sclerenchymatous cells. Two types of sclerenchyma cells exist-fibres and sclereids. Their walls consist of cellulose, hemicellulose, and lignin. Sclerenchyma cells are the dead cells in plant tissues that play a vital role in providing mechanical support to the plants.

Detailed explanation-4: -Lignin is an organic substance belonging to a group of aromatic alcohols. It is naturally produced by certain plants (especially woody plants and certain algal species). It is found in the secondary cell walls of plants where it serves as a binder for cellulose fibers and provides stiffness to the cell walls.

Detailed explanation-5: -Collenchyma tissues have a polygonal shape of living cells with corners thickened with cellulose and pectin. Shape of the schlerenchyma cells are elongated and cell walls are thickened by lignin.