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Author Question: A number of mechanisms operate to maintain genetic diversity in a population. Why is such diversity favored? (Read 749 times) |
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.
Critical care patients are twice as likely to receive the wrong medication. Of these errors, 20% are life-threatening, and 42% require additional life-sustaining treatments.