A 'Trend' is a large social influence if this is what you are talking about. Trends are something where one person does/wears it (usually a popular person everyone likes) and then everyone else starts doing it.
Answer:
The answer is B.
Explanation:
A non-rebreather mask can deliver levels of the fraction of inspired oxygen (FIO2) as high as 100%.
Answer: Complementary medicine.
Explanation:
Complementary medicine is defined as the set of therapeutic techniques that are not part of conventional medicine. These, as their name says, are a complement, not the first option when treating a patient. Some complementary medicine techniques are meditation, hypnosis, acupuncture, and massage.