Which of the following functions is not performed by smooth muscle?
Regulation of blood pressure
Movement of food through the digestive system
Contraction of the heart
Constriction of blood vessels
Smooth muscle is a type of muscle tissue that is found in the walls of internal organs and blood vessels. It is responsible for a variety of involuntary movements, such as the regulation of blood pressure, movement of food through the digestive system, and constriction of blood vessels. However, the contraction of the heart is not performed by smooth muscle. The heart has its own specialized muscle tissue known as cardiac muscle, which is striated in appearance but is not under voluntary control. Hence, option 3 is the correct answer.