The common name for the substance that makes up the cell wall of plants is cellulose. Cellulose is a complex carbohydrate, specifically a polysaccharide, that provides structural support and rigidity to plant cells. This fibrous substance enables plants to maintain their shape and resist external pressures. Additionally, cellulose plays a crucial role in the overall health of ecosystems, as it is a primary component of dietary fiber for various organisms, including humans. Its abundance in the environment underscores its significance in industries such as paper production and biofuel development.