The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
Generally, the sun observes a solar cycle of eleven years. In this cycle, there are fluctuations in the activity, such as the ejected levels of solar radiation, and in the appearance of the sun, such as changes in the amount and size of sun spots, solar flares and other phenomena that occur on the sun's surface.
These changes also affect phenomena on earth, especially the auroras.
Proteins function optimally at a specific temperature. So if you get too hot or too cold, biochemical reactions in your body start to function less well. If the situation becomes extreme enough, they can cease to function well enough to sustain life.
Warm-blooded animals have an advantage over cold-blooded ones in that their bodies automatically try to maintain the optimal termperature for things in their bodies to function. Cold-blooded animals depend on the environmental temperature to do this for them. That's why reptiles are very sluggish when they're cold, but will "wake up" when they get warm.
The cost to this benefit is that metabolically, warm-blooded animals require a lot more fuel to run their bodies. It's very energy-intensive to maintain a constant body temperature. Cold-blooded animals require far less fuel than warm-blooded ones relative to their size.
The way that proteins operate in a specific temperature is also true of the pH in your body which is also very tightly maintained.
