Question

1. _______ stimulate(s) milk production after childbirth.

Answer 1

1. Prolactin stimulates milk production because after the placenta is delivered the absence of progesterone and high levels of prolactin cause milk production.
5. Dextromethorphan is used to treat common colds and contains anti-histamines, pain relievers and decongestants.
13. Receiving oxygen is the main goal of the respiratory system by acting as a vacuum to suck in air and release carbon dioxide.
19.Cardiopulmonary rescucitation is used to get blood flowing and the lungs working by using chest compressions and artificial air flow. The chest compression at like jump start to get the heart pumping and lungs inflating.
20. Norepinephrine works with the sympathetic nervous system to activate the fight or flight response and release adrenaline to either fight or run. 
I tried to answer all of these questions but I don't think I can answer all twenty all at once