I would say tested anything scientific comes w a hypothesis and gets tested.
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 belive its called a metric system
Answer 1)
Not 2 bc they don’t come from the soil, they are made by plants through photosynthesis.
Not 3 bc I’m pretty sure sugar is not the only source of food for plants.
Not 4, I’m not exactly sure why not 4, but my gut is saying 1.
Sorry the explanation is not super helpful.