During the alarm stage, what substance does the body release that triggers responses to a threat?

The correct answer is - Adrenaline.

Explanation:

Adrenaline is the substance or the hormone that releases by the body in the blood in a stress condition or during the alarm stage. Adrenaline release in the blood causes several immediate changes in the body.

These changes include; breathing rate increases, increase in the blood flow to the brain, blood pressure and heart rise and pupils widened up, the sugar level in the blood rises, the ability of blood cot increases, digestion slows down, more acid produced in digestive tracts and many more that help in fight or flight.

Thus, the correct answer is - adrenaline.

because health skills are tools and strategies and also practical skills are also something you need to learn (like tools and strategies) and put it in reality.