There is a hormone called epinephrine, also known as adrenalin. This may be what you are wondering about.
wot causes hyperness and how does the body react to it.
the thyroid gland
because it makes you react quickly by using fast twitch fibres in your body which makes your muscles react.
Your reflexes automatically make you react to things without you knowing it. You react to someone throwing something at you to protect your body.
Electric signals interpreted by your brain.
Hormones
Metals taken as micronutrients, in the body are dissolved in water; it is not a chemical reaction.
Yes, fear can cause pupils to constrict. When the body experiences fear, the sympathetic nervous system is activated, leading to the release of adrenaline. Adrenaline causes the pupils to constrict, allowing the individual to focus on a threat and react quickly.
Epinephrine (called adrenaline in non-US English speaking countries)
pheromone
A chemical reaction in their body causes them to "electricute" people.
Diarrhea is caused by bacteria entering your body/ through your food. Which causes the body to try and get rid of the bacteria as quickly as possible which causes runny faeces or vomiting.