Final answer:
The statement is true as the intestines contain an inner circular and an outer longitudinal layer of unitary smooth muscle that are essential for peristalsis in the GI tract.
Step-by-step explanation:
The statement that cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine is True. Cells of unitary smooth muscle are indeed found in the longitudinal and circular muscle layers of the intestine. The muscular layers of the gastrointestinal (GI) tract, including the intestines, consist of an inner circular muscle layer and an outer longitudinal muscle layer. These layers are responsible for the peristalsis of the intestinal tract, aiding in the mechanical digestion and propulsion of food through the alimentary canal.