Which Is a Physiological Description Rather Than an Anatomical One

Which is a physiological description rather than an anatomical one?

A) The muscles of the intestinal wall contract slowly and involuntarily.
B) The walls of blood capillaries are composed of a thin epithelium.
C) The muscles of the thigh are composed of skeletal muscle tissue.
D) There are fenestrations (openings) in the epithelial cells of capillary walls.
E) The esophageal wall includes a middle layer of dense irregular connective tissue.