Hey there! I'm happy to help!
The cerebellum is in the back of the brain and it helps with balance and reflexes, but it isn't part of the actual brain stem, so that is not the right answer choice.
The cerebrum is the front part of the brain made up of the many different lobes. Its ultimate goal is to help with thought, movement, and language. This is not part of the brain stem.
The brain stem consists of the midbrain, medulla, and pons. The midbrain is the uppermost part with the pons below it and the medulla oblongata below the pons.
The midbrain is important for functions such as eye and body movement. The pons aids with body signaling and the medulla oblongata also aids with reflexes and involuntary actions (as it is close to the cerebellum). The brain stem as a whole helps with respiration, heart rate, and blood pressure.
Have a wonderful day and keep on learning! :D
