I think it is beneficial for the brain to be connected to the contralateral side of the body because of the position and connection to the brain that our eyes have. Because light from the right visual fields strikes the left side of the eye and light from the left side strikes the right side of the eye, the connections allow visual information from both sides of the body to reach the brain.
Because the cell is considered an organelle which is a biological mechanism which consists of different parts, whereas a molecules is a single part and not a mechanism.
