00:01
The part of the lungs where oxygen and carbon dioxide are exchanged is the trachea, the alveoli, the bronchioles or the bronchi.
00:11
So if we look at the structure of the lungs, we have the central windpipe, and this is called the trachea, so that we'll label as a, and then it splits off into the two lungs.
00:22
So these two splitting off points, each of which goes to a long, these are called the bronchae.
00:30
So bronchus, singular, together the bronchae.
00:38
And from there, they split off into even smaller vessels.
00:43
And these vessels get smaller and smaller.
00:45
So we have a series of bronchye and a series of bronchials.
00:50
And eventually, they end up in these little sacks.
00:55
So these sacks are single cell thickness and they are lined with capillaries.
01:06
So you have the air that you inhale, a single cell for the lining here, a single cell for the capillary wall, and then the blood.
01:15
So that is where we get gas exchange.
01:19
And these are called the alveoli.
01:22
So the answer is b...