Answer: norepinephrine
Step-by-step explanation:
Norepinephrine is a chemical in our body system that simply functions as a neurotransmitter that is, it helps to send signals between the nerve cells in our body and also acts as a stress hormone.
When the brain feels that we are going through a stressful moment, norepinephrine is then released in the blood. Norepinephrine helps increases the heart rate and give more energy to our body.