What are three distinguishing features of epithelial tissue?

• A. Polarity, avascularity, high regenerative capacity; supported by the basement membrane.
• B. Avascularity, presence of abundant extracellular matrix, and high metabolic activity.
• C. Highly contractile fibers, neural innervation, and motility.
• D. Capillary-rich vascular supply, strong cartilage support, and endocrine secretion.

Answer: (A)

Epithelial tissue is defined by three key features: polarity, avascularity, and a high regenerative capacity, all anchored by the basement membrane. Polarity means cells have distinct apical and basal surfaces, with specialized features (like microvilli or cilia) on the apical side and attachment to the basement membrane on the basal side. Avascularity indicates there are no blood vessels within the epithelium; nutrients reach cells by diffusion from underlying connective tissue. High regenerative capacity comes from stem cells in the basal layer that continuously divide to replace lost or damaged cells, enabling rapid repair. The basement membrane underpins all these traits by providing structural support and helping organize and anchor the tissue to the underlying connective tissue. This combination—polarity, avascularity, and high renewal, all supported by the basement membrane—best describes epithelial tissue, whereas the other statements reflect features of muscle, connective tissue, or glands rather than epithelium.