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Author Question: Exhibit 5-2 A 4.00 kg block is suspended from the roof of an elevator. A 2.00 kg block is suspended ... (Read 2215 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.
More than 150,000 Americans killed by cardiovascular disease are younger than the age of 65 years.
In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.