Final answer:
The three major portions of the brain are the d)cerebrum, cerebellum, and brain stem. The cerebrum is responsible for conscious thought and voluntary muscle movement, the cerebellum is involved in coordinating movement and balance, and the brain stem controls vital functions.
Step-by-step explanation:
The three major portions of the brain are the cerebrum, cerebellum, and brain stem.
The cerebrum is the largest part of the brain and is responsible for conscious thought, sensory perception, and voluntary muscle movement.
The cerebellum is located at the back of the brain and is involved in coordinating movement, balance, and posture.
The brain stem is located at the base of the brain and connects the brain to the spinal cord. It controls vital functions such as breathing, heart rate, and blood pressure.