Answer:
The squamous epithelial cells are round, small, flat nucleated cells comprising small nucleus. The outline of the cells is regular and the cells in combination produce a lining or covering. When these cells get aligned as simple epithelia, that is, in a solitary layer of cells, they help in the process of diffusion by allowing the nutrients to come within and the cellular waste substances to move out from the cell. For example, the blood capillaries that take part in the interchange of wastes and nutrients in the blood.
On the other hand, when the squamous epithelial cells are aligned in a stratified form, that is, in the form of various layers, they safeguard the body from destruction and outer abrasion. For example, the tissues and skin covering the vagina and mouth comprise stratified squamous epithelial cells.