These alveoli are the smallest types of lung tissue, and one of the most important. In addition to being the primary means by which oxygen enters and carbon dioxide escapes the bloodstream, these small pouches of air are also the reason why the lungs do not totally collapse when a person breathes out. This is because they contain a cell that secretes a special chemical to lower the surface temperature to prevent lung collapse. The alveoli also contain other cells that secrete chemicals to attack and remove any foreign objects in the lungs, such as dust, dirt and other debris.
In addition to making up alveolar sacs, alveoli also form alveolar ducts. It is estimated that there are more than 300 million alveoli in the human lungs, all of which are located in either alveolar ducts or sacs that are found at the end of the smaller passageways, or bronchioles, in the lungs.
SHORT ANSWER:
Alveolar sacs contain tiny pouches called alveoli, whose primary function is gas diffusion. These clusters of alveoli have thin walls that allow oxygen to pass easily from the lungs into the bloodstream and carbon dioxide to flow from the blood to the lungs so it can exit the body.
Answer:
1/4
Explanation:
A heterozygous woman for both traits (RrFf) marries with a man with no freckles (ff) who can't roll his tongue (rr).
The cross is: RrFf X rrff.
The woman can produce the gametes <em>RF, Rf, rF </em>and <em>rf</em>
The man can only produce <em>rf </em>gametes.
<u>The possible offspring that can arise from the combination of those gametes is:</u>
- 1/4 RrFf Freckled, tongue-rolling
- 1/4 Rrff Freckled, unable to roll tongue
- 1/4 rrFf Not freckled, tongue-rolling
- 1/4 rrff Not freckled, unable to roll tongue
Carbon Dioxide (CO2) because it is essential to cellular processes that allow plants to thrive and generate oxygen that we can breathe. Nitrogen could also be an example of one gas that's important.
