C. The material for it is super expensive and sometimes fragile, which sucks, but it's true.
Answer:
C) They are compressed during inhalation.
Explanation:
Birds breathe through rigid lungs that are located in the animal's thoracic region. The trachea of birds divides into bronchi that branch inside the lungs into very thin tubes called parabronchials or parabroncholes, which are irrigated by blood capillaries that allow gas exchange.
In birds there are no pulmonary alveoli (as in mammals), but air capillaries that depart from the parabroncholes. Oxygen gas passes from these capillaries to the blood capillaries, thus causing gas exchange.
In the lower portion of the bird's trachea, before branching the bronchi, we can find the syringe, a bag-like structure that has vocal cords responsible for the birds' scream and song. Most of the time, the sound emitted by birds serves to attract the mate, mark territory and prevent birds of the same species against some predator or other danger.
Explanation:
The act of aspiring or ardently desiring; an ardent wish or desire, chiefly after what is elevated or spiritual (with common adjunct adpositions being to or of)
the main human activity is air pollution
