The left cerebral hemisphere controls:

• A. the right side of the body.
• B. heart rate and pupil reaction.
• C. breathing and blood pressure.
• D. the right side of the face.

Answer: (A)

Motor control is contralateral: the left hemisphere’s motor regions send signals down pathways that cross to the opposite side, so they primarily control muscles on the right side of the body. This wiring explains why a left-hemisphere injury can cause weakness or paralysis on the right. Functions like heart rate, pupil reaction, breathing, and blood pressure are managed by autonomic centers in the brainstem, not by one hemisphere, so they aren’t said to be controlled by the left side. The face involves more complex innervation, with substantial bilateral input, so stating it as simply “the right side” of the face isn’t as accurate as describing limb motor control.