Final answer:
A lesion in the left precentral gyrus results in paralysis of the right side of the body due to the control of voluntary muscle movement by the contralateral motor cortex. correct answer is a) paralysis of the right side of the body.
Step-by-step explanation:
A lesion in the left precentral gyrus would result in paralysis of the right side of the body (option a). This is because the precentral gyrus, also known as the primary motor cortex, controls the voluntary movements of muscles on the contralateral (opposite) side of the body through the corticospinal tract. The left hemisphere of the brain, where the left precentral gyrus is located, is responsible for motor commands that affect the right side of the body. Hence, if the left precentral gyrus is damaged, it would lead to paralysis on the right.
Furthermore, the left hemisphere is also dominant for language in most people, which means Broca's aphasia, characterized by the loss of the ability to produce language, typically occurs with damage to the left hemisphere as well. However, lesions specifically to the precentral gyrus do not cause language deficits as these are associated with different areas, like Broca's area for expressive language, located in the frontal lobe but not within the precentral gyrus itself.