Answer:
stationary
Explanation:
It's called a stationary front because the gases remain stationary next to each other because neither is strong enough to replace another.
The alveolus (singular form) or alveoli (plural
form) are tiny sacs of organs that are attached to the ends of the alveolar
duct. These tiny sacs of air are clumped together that form interconnected
caves, working together as a unit. They are found inside the lungs and they
make the exchange of air easy and possible. Alveoli units are responsible for
putting oxygen into the air that we breathe in. Blood that passes through the
heart and into the lungs are converted into oxygen which will be then
transported by the blood all over the body systems.
<span>
The walls of the alveoli are extremely thin to
enable the quick exchange of gases Aside from this, the linings of alveoli
units are fluid in nature enabling gases to dissolve. </span>
I believe it would be option A. If it still doesn't answer your question, don't hesitate comment below. :)
I believe the correct answer is c. obtain nutrient molecules
