Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

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

A.B.C.C.CD.A.BC.B.D Im sure

I believe the correct answer is B. Nephridia are excretory organs. They are organs found in invertebrate animals that are present in pairs and are responsible for performing functions that are similar to the kidney of a vertebrate. They excrete wastes from metabolic processes.

Mouth,Pharynx,Larynx.Trachea,Bronchi and Bronchioles,Lungs,Muscles of Respiration.

There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration. The airway, which includes the nose, mouth, pharynx,larynx, trachea, bronchi, and bronchioles, carries air between the lungs and the body's exterior. and the lungs