I believe the answer to your question will be atrioventricular but don't cross out pulmonary it could possibly be the answer.
It would affect the respiratory system
Answer:
The answer is 2: A series of physical and psychological reactions that occur when you respond to a demanding or threatening situation.
Explanation:
Process of elimination:
1 - You can never completely eliminate stress
3 - Stress doesn't always manifest for a physical threat, it can form because you have a test next period or because you have an upcoming project,
4 - Stress is not always harmful, it also can come and go and you might even feel better afterwards, as in cases of physical stress.
