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Author Question: The ozone layer is a. transparent to ultraviolet radiation. b. opaque to ultraviolet radiation. ... (Read 53 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.
Chronic marijuana use can damage the white blood cells and reduce the immune system's ability to respond to disease by as much as 40%. Without a strong immune system, the body is vulnerable to all kinds of degenerative and infectious diseases.
The average office desk has 400 times more bacteria on it than a toilet.
The longest a person has survived after a heart transplant is 24 years.
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.