Which type of weakness refers to only one side of the body being affected?

The correct choice is based on the understanding of the terms used to describe various types of motor weakness. Hemiparesis specifically refers to weakness on one side of the body, typically resulting from a neurological injury such as a stroke or brain damage affecting the opposite side's motor control center. This condition leads to a partial loss of strength and control, thus aligning with the definition of weakness affecting one side.

In contrast, hemiplegia describes complete paralysis on one side, while quadriplegia involves paralysis of all four limbs. Monoplegia denotes weakness or paralysis in a single limb, making hemiparesis the most precise term for discussing weakness limited to one side of the body.