Answer :
Gray commissures are necessary for contralateral pathways, which are pathways where signals cross over to the opposite side of the body, such as in the corticospinal tract. The correct option is A.
The gray commissures are necessary for contralateral pathways. These pathways involve nerve impulses or signals crossing over from one side of the body to the opposite side. This is typical in several neural pathways, such as those making up parts of the corticospinal tract. In the corticospinal tract, axons originating in the motor cortex cross the midline at the medulla's base, indicating a contralateral organization. Therefore, the right motor cortex controls muscles on the left side of the body and vice versa.
