Which of the following is not a characteristic of smooth muscle?

Smooth muscle is characterized by its lack of striations, which distinguishes it from skeletal and cardiac muscle. This absence of striations is due to the organization of the contractile proteins in smooth muscle, which are not arranged in the highly structured pattern seen in the other types of muscle.

Smooth muscle also has the ability to undergo mitosis, allowing for regeneration and repair. Its fusiform shape, which means it tapers at both ends, contributes to its function in various hollow organs such as blood vessels and the digestive tract. Importantly, smooth muscle operates under involuntary control, meaning it is not consciously directed by the nervous system, but rather regulated by autonomic signals and hormonal influences.

Thus, the distinguishing feature of smooth muscle regarding its lack of striations is why this characteristic is the correct answer to the question posed.