Answer: only one gland in the body
The atmosphere which is the lowest layer
Answer
Elastin fibers are glycoproteins found in the lungs and are usually in large quantities. The abundant elastin fibers are helpful in the recoil process of the lungs after being expanded by the muscles of the respiratory system.
During inhalation,the diaphragm and intercostal muscles expand the chest. This forms a negative pressure and draws the air in.The Lungs recoil to expel used up air during exhalation.
