What is the primary function of the cell wall?

The primary function of the cell wall is to provide structure and protection primarily to plant cells and some bacteria. The cell wall is a rigid layer located outside the cell membrane that gives the plant cell its shape and helps maintain turgor pressure, which is crucial for the plant's structural integrity. In plants, the cell wall is mainly composed of cellulose, which offers resistance against mechanical stress and serves as a barrier against pathogens.

In addition to plants, some bacteria also possess cell walls, which serve similar protective and structural roles. The presence of a cell wall allows these organisms to withstand osmotic pressure and provides them with a certain amount of rigidity and support.

Other choices highlight different functions or characteristics that do not accurately describe the primary role of the cell wall. For example, while animal cells have a cell membrane for protection and structure, they do not possess a cell wall. Furthermore, nutrient absorption in plants primarily occurs through root systems and the cell membranes, not the cell wall. Likewise, the regulation of substance movement into and out of cells is mainly the function of the cell membrane, rather than the cell wall, which does not have the same selective permeability.