Final answer:
The cerebellum is responsible for balance and movement coordination, not the cerebrum, brain stem, medulla oblongata, or hippocampus as listed in the question options.
Step-by-step explanation:
The portion of the brain responsible for balance and movement is known as the cerebellum. Contrary to the options provided in the question which were cerebrum, brain stem, medulla oblongata, and hippocampus, the correct answer is not listed.
The cerebellum, often referred to as the "little brain", is situated at the base of the brain on top of the brainstem. Its primary function includes controlling balance and aiding in the coordination of movement and learning new motor tasks. As we learn skills through repeated practice, such as playing an instrument or sports, it is the cerebellum that helps fine-tune these coordinated movements.