Exercise programs and sports activities can differ in number of participants from one person doing an activity like jogging or swimming, to hundreds of participants at a track meet. Structure can be loose in solo exercises where you can set your own pace, or be very strict in most competitive sports. Competition varies from none to highly competitive, and can be on an individual or team level. More complex sports and activities can present a high skill level.
Gases can be produced by normal flora (bacteria that normally lives in the intestines) and harmful bacteria as well.
Under the Berlin definition, patients with PaO2/FiO2 200-300 would now have "mild ARDS." Onset of ARDS (diagnosis) must be acute, as defined as within 7 days of some defined event, which may be sepsis, pneumonia, or simply a patient's recognition of worsening respiratory symptoms.
And the peripheral nervous system
Cheese is a good source of dairy. Most dairy products have calcium which you need for healthy teeth and strong bones