Answer: A. The Pineal body
Explanation: The pineal gland is responsible for releasing melatonin in response to a dark environment.
B. The cerebellum is largely responsible for motor functions such as walking and balance.
C. The hypothalamus is largely responsible for maintaining homeostasis within the body through the control of the autonomic nervous system and various hormones.
D. The corpus callosum is the "bridge" that helps the two hemispheres of the brain communicate with one another.
E. The hippocampus is largely responsible for learning and memory.
