Which of the following is NOT classified as epithelial tissue?

Cancellous tissue, also known as spongy bone, is classified as a type of connective tissue rather than epithelial tissue. Epithelial tissues primarily serve functions such as protection, absorption, secretion, and sensation, and they are characterized by closely packed cells with minimal extracellular matrix.

In contrast, cancellous tissue has a specific structure that includes a network of trabeculae which is designed to provide structural support and house bone marrow. This distinct characteristic differentiates it from epithelial tissues like simple columnar, cuboidal, and stratified squamous, all of which are directly involved in various protective and functional roles in the body related to surfaces and linings. Therefore, understanding the roles and definitions of different tissue types helps clarify why cancellous tissue does not fit into the epithelial classification.