What characterizes marked hyperactivity?

Marked hyperactivity is primarily characterized by excessive movement and physical activity that can significantly impact a person's ability to engage in typical or expected behaviors. Choosing the act of running instead of walking highlights this excessive physical activity. In many cases, individuals who are hyperactive may find it difficult to control their impulses, resulting in what can be described as an energetic or overactive demeanor.

While other options might describe behaviors associated with attention-related disorders, they do not specifically emphasize the physical aspect of hyperactivity in the same direct way as running instead of walking does. This movement reflects a hallmark of hyperactivity, illustrating the inability to remain still or adhere to a slower pace that is often expected in various social settings.