The cells of stratified squamous epithelium are arranged in many layers. Why?

How are epithelial tissue classified on the basis of cell shape and arrangement?

Name the type of tissue present, where transportation of substances occurs through the selectively permeable membrane.

The sites where cuboidal epithelium is present, will be specialized in which type of functions?

In which type of epithelium, cilia are present? What is their role in this epithelium?