Which type of "proper" connective tissue includes the dermis?

Dense irregular connective tissue is indeed the type of "proper" connective tissue that includes the dermis. The dermis, which is the thick layer of skin beneath the epidermis, comprises a complex network of collagen and elastin fibers, which provide strength and elasticity. This type of connective tissue is characterized by its irregularly arranged collagen fibers, which allows it to withstand stress from various directions, essential for the skin’s function and stability.

In contrast, other types of connective tissues mentioned do not provide the same properties required for the dermis. Areolar tissue, while providing some support and elasticity, is typically found in more superficial areas and serves primarily as a loose connective tissue. Dense regular connective tissue, characterized by its orderly, parallel arrangement of collagen fibers, is found in tendons and ligaments where force is applied in a single direction. Lastly, reticular connective tissue primarily forms a supporting framework for organs like the liver and spleen, rather than a structural foundation for the skin. Hence, the unique structural characteristics of dense irregular connective tissue make it the appropriate choice for the dermis.