Because the brain stem is what transfers all information to the rest of your body. Also, it is directly connected to the hypothalamus, which if damaged, can take away your ability to breathe or do simple tasks.
Answer: 5(last one :regulation of circulatory system)
You would use a open stance.
He is not coming big fella
For this answer I would go with D. Retinalogic. It is not a vitamin.