What type of muscle is primarily found in the digestive tract and blood vessels?

Smooth muscle is the correct answer because it is the type of muscle that is primarily found in the walls of hollow organs, including the digestive tract and blood vessels. This muscle type is involuntary, meaning it operates without conscious control, which is essential for processes such as peristalsis in the digestive tract and the regulation of blood flow through arteries and veins.

Smooth muscle cells are spindle-shaped and do not have the striations seen in skeletal and cardiac muscles. This lack of striation is a defining characteristic of smooth muscle, which allows it to function effectively in the slow, sustained contractions needed for digestion and vascular functions. Additionally, the ability of smooth muscle to contract and relax gradually helps maintain essential bodily functions without the rapid fatigue associated with skeletal muscle.