You fall backeard and hit your head very hard on sharp rock. The blow to your head causes you to lose consciouness and stop breathing. You most likely hot what part of your brain? Cerebellum. Frontal lobe. Brain stem.

Brain stem

Explanation:

The cerebellum is key to maintaining balance and coordination, not involuntary actions such as breathing.

The frontal lobe of the brain is responsible for things like emotions, memory, and language. Not breathing and consciousness. Plus, the frontal lobe is at the front of your brain, and you hit the back of your head.

But the brain stem is responsible for breathing, swallowing, heart rate, consciousness, and other involuntary actions your body does.