|
Author Question: When a researcher manipulates two independent variables simultaneously, the appropriate analysis ... (Read 41 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.
Many supplement containers do not even contain what their labels say. There are many documented reports of products containing much less, or more, that what is listed on their labels. They may also contain undisclosed prescription drugs and even contaminants.
Asthma cases in Americans are about 75% higher today than they were in 1980.
More than 30% of American adults, and about 12% of children utilize health care approaches that were developed outside of conventional medicine.
Since 1988, the CDC has reported a 99% reduction in bacterial meningitis caused by Haemophilus influenzae, due to the introduction of the vaccine against it.