Final answer:
Epithelial membranes are attached to a layer of connective tissue by the basement membrane, which is composed of basal and reticular lamina.
Step-by-step explanation:
Epithelial membranes are attached to a layer of connective tissue by a layer of proteins and polysaccharides called the basement membrane.
The basement membrane is composed of a basal lamina, which is secreted by the underlying connective tissue, and a reticular lamina. It helps hold the epithelium and connective tissue together.