The options to choose from are: portal of exit, reservoir, portal of entry
The answers are JoAnn is the reservoir in the chain of transmission. The mucus from her cough is the portal of exit in the chain of transmission.
JoAnn is the reservoir because the cold is stored in her body. The mucus is the portal of exit because it is being coughed up outside the body.
Answer: Endorphins
Explanation: Endorphins are chemicals secreted by the brain also known as neurotransmitters that send electrical signals inside the nervous systems.
The factors that initiate the secretion of endorphins are stress and pain.
When endorphins are secreted they reduce feelings of pains, and in runners that cause a phenomenon called " Runners high" which allows runners to keep running without feeling pain or stress.
I would say the last option students who bring weapons to school are acting on the rage they feel as victims of harassment.
