From mouth/nose, the air passes to the trachea (the wind pipe), there it enters (sequentially) the bronchi, bronchioles (small pipe-like structures), alveoli (widened empty sacs), the walls of which are in close contact with the blood vessels which contain the RBCs, which in turn contain the protein--hemoglobin, which binds to the oxygen present in the freshly inhaled air, and loses the carbondioide present DISSOLVED in the blood. This bound oxygen goes to the heart (of course along with the RBCs in the blood), from there to the smaller and smaller arteries, then to the capillaries, where again oxygen is lost to the surrounding tissue fluid, from where the cells collect oxygen by simple diffusion, and lose carbon dioxide, which gets dissolved in the water present in the blood.
From here the blood, with hemoglobin poorer in oxygen, and richer again in carbondioxide goes to the venules, and veins (capillaries continue as venules), which become successively larger to become superior and inferior vena cava and enter the right atrium, and then from there the blood again goes to the lungs and comes in contact with fresh air in the alveoli.
The second one changes in the amount of atmospheric gases because it think it might effect everyone including plants and animals because will all breath the same air rather than a mountain building it might affect the animals that like there.
Subculture. A subculture is a group of people within a culture that differentiates itself from the parent culture to which it belongs, often maintaining some of its founding principles. Subcultures develop their own norms and values regarding cultural, political and sexual matters.