• The pharynx, or throat, is the passageway leading from the mouth and nose to the oesophagus and larynx. 
• The pharynx permits the passage of swallowed solids and liquids into the oesophagus, and conducts air to and from the trachea, or windpipe, during respiration. 
• The pharynx also connects on either side with the cavity of the middle ear by way of the Eustachian tube and provides for equalization of air pressure on the eardrum membrane, which separates the cavity of the middle ear from the external ear canal. Hence, The short tube leading from the nose is pharynx.

• The diaphragm is a part of the abdominopelvic cavity.
•  It is located below the thoracic cavity and above the pelvic cavity.
•  Its dome-shaped roof is the thoracic diaphragm, a thin sheet of muscle under the lungs, and its floor is the pelvic inlet, opening into the pelvis. Hence, the diaphragm is a dome-shaped muscle.

• The nasal cavity and the mouth meet at the pharynx, or throat, at the back of the nose and mouth. 
• From there, air quickly enters the second part of your respiratory system, the trachea or windpipe. 
• The trachea is a tube that delivers air to the lungs, the third and most important part of your respiratory system. Hence, Air goes from the pharynx to. trachea.

• The bronchi (or bronchus) are the air passages into the lungs that begin at the end of the trachea. 
• There are two bronchi, one for each lung. 
• The bronchus divides into smaller branches known as segmental bronchi, which divide again into bronchioles, Hence, Bronchi divide into bronchioles.

Respiratory quotient if the protein is 0.8-0.9