Which of the following hormones is suddenly secreted into the bloodstream of a frightened person?

When a person is frightened, the hormone adrenaline is suddenly secreted into the bloodstream. This hormone, also known as the "fight or flight hormone," prepares the body for a sudden burst of energy and increased physical activity. It increases heart rate, breathing rate, and blood pressure, and redirects blood flow to the muscles and away from less essential organs. This prepares the body to respond quickly and effectively to a perceived threat.