What is the primary function of epithelial tissue?

Epithelial tissue plays a crucial role in the body primarily through its functions of protection, absorption, and secretion. This type of tissue forms the protective layers covering the surfaces of organs and structures throughout the body. For instance, the skin consists of epithelial tissue that protects underlying structures from mechanical injury, pathogens, and dehydration.

Additionally, epithelial tissue is involved in absorption, particularly in organs such as the intestines, where it facilitates the uptake of nutrients into the bloodstream. Certain epithelial tissues also have specialized functions in secretion, such as glandular epithelium, which produces and releases hormones, enzymes, and other substances.

The other functions mentioned, like transportation of substances, movement of body parts, and signal transmission, are primarily associated with other tissue types. Connective tissues are more involved in transportation (for example, blood), muscle tissues facilitate movement, and nervous tissues are responsible for signal transmission within the body. Therefore, the choice highlighting protection and absorption accurately represents the primary function of epithelial tissue.