|
|
Stroke kills people from all ethnic backgrounds, but the people at highest risk for fatal strokes are: black men, black women, Asian men, white men, and white women.
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
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.
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
Vaccines prevent between 2.5 and 4 million deaths every year.
![Distribution of glaciers in North America (a) in the late twentieth century, and (b) 18,000 years ag](https://biology-forums.com/gallery/47/medium_33_19_02_12_5_39_50_20561464.jpeg)
![Laparoscopy. A lighted endoscope specialized for insertion into the abdomen, called a laparoscope, i](https://biology-forums.com/gallery/47/medium_14755_16_10_12_12_29_16_94431165.jpeg)