Final answer:
Skeletal muscle is differentiated from cardiac and smooth muscle by its multinucleated fibers, where many nuclei are present within one long, cylindrical cell. This contrasts with cardiac muscle, which has only one to two nuclei per cell, and smooth muscle, which typically has a single nucleus per cell.
Step-by-step explanation:
The characteristic that differentiates skeletal muscle from both cardiac and smooth muscle is the presence of multinucleated fibers. While all three types of muscle tissue have the ability to generate force and require stimulation to contract, skeletal muscle fibers are unique in that they are long, cylindrical cells that contain many nuclei. These nuclei result from the fusion of myoblasts during development, forming large, multinucleated fibers. Unlike skeletal muscle, cardiac muscle fibers contain only one to two nuclei, and smooth muscle fibers typically have a single nucleus. Additionally, skeletal muscle is under the control of the somatic nervous system, meaning it is voluntarily controlled, whereas cardiac and smooth muscle contractions are usually involuntary and controlled by their own internal pacemaker cells or the autonomic nervous system.