Building models doesn't actually help scientists observe phenomena. Scientists build models to describe how nature and systems operate then make observations to see if their models match what they observe. Models which don't match what they observe are either alterated or scrapped. Good models are kept and used by the scientific community.
The correct answer among the choices provided is option A. Lung capillaries are responsible for exchanging carbon dioxide for oxygen from the air. Blood that comes from the heart gets oxygen from the alveoli. The carbon dioxide in the blood goes into the alveoli at the same time.
<span>In order for a climate to be considered "arid", a region/land must have scare rain that does not support the growth of vegetation. It is thought to be an areas that has minimal water sources that cannot produce greenery or other foliage. Arid can be considered extremely dry which will impact the surrounding land's ability to support growing life including plants and other animals.</span>
It makes you a better member of society because you will be more knowledgeable