00:01
To answer this question, let us understand four points.
00:03
So first point is birds have air sacks in various body parts.
00:18
So when birds take in air, these sacks also fill.
00:32
And air sacks are both anterior and posterior in nature.
00:41
Whereas birds ' lungs are static, that is, they don't move.
00:48
So the oxygenated air, it remains for two complete inhalation and exhalation cycle before it is fully used.
01:19
So in this case, due to air sacks, they hold air for longer duration.
01:37
Because of this, they also get more area for diffusion of air.
01:55
The air flow is from trachea to posterior air sac and anterior air sac.
02:15
So this is a movement for the air in case of birds and this is filled by previous ear of lung which is residual.
02:24
So already there was air present in the lung which is called as the residual air...