Question

Mechanism of breathing very among different groups of animals depending on :

Answer 1

Breathing involves two stages:

INSPIRATION:

• Inspiration during which atmospheric air is drawn in.
  
• At the time of inspiration, contraction in diaphragm and external intercostal muscles takes place.
  
• Normally it takes around 2 seconds.

EXPIRATION:

• Expiration is a process by which the alveolar air is released out.
• At the time of expiration, contraction does not take place.