epithelium can function in diffusion, filtration, secretion and protection based on location.

The given blank can be filled with simple squamous epithelium.

Explanation:

The tissues produced from a single layer of squamous cells, which lines the surfaces are known as simple squamous epithelia. These cells are thin, large, and flat and comprise a rounded nucleus. These tissues exhibit polarity and comprise a distinct apical surface like other epithelial cells with unique membrane proteins.  

This epithelium is found generally in the areas where the transportation or absorption of substances takes place. They also perform a key role in osmosis, diffusion, and filtration. Apart from this, it is also protective and secretory in function. Simple squamous epithelium is commonly found in the alveoli of the lungs, in the kidney and in the walls of capillaries.