Final answer:
Simple squamous epithelium is best suited for diffusion due to its flat, thin, single-layer arrangement, which allows for efficient gas, nutrient, and waste exchange.
Step-by-step explanation:
The type of epithelial cell best adapted to aid diffusion is the simple squamous epithelium. These are flat cells arranged in a single layer which facilitate efficient diffusion. This is because they present the minimal barrier to substances moving by diffusion due to their thinness and single layer arrangement, making them particularly suited for areas of gas and nutrient exchange, such as in the alveoli of the lungs and the lining of blood capillaries.
Simple squamous epithelia allow not only for the diffusion of gases but also nutrients and waste. In contrast, stratified epithelia, like stratified squamous, are thicker and consist of multiple layers, thus providing protection rather than facilitating diffusion. Cuboidal cells, being thicker and cube-shaped, are less efficient in diffusion compared to the flat squamous cells.