|
|
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
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.
People with alcoholism are at a much greater risk of malnutrition than are other people and usually exhibit low levels of most vitamins (especially folic acid). This is because alcohol often takes the place of 50% of their daily intake of calories, with little nutritional value contained in it.
In ancient Rome, many of the richer people in the population had lead-induced gout. The reason for this is unclear. Lead poisoning has also been linked to madness.
The human body produces and destroys 15 million blood cells every second.
![Three principle forms of natural selection: (a) stabilizing selection, (b) directional selection, an](https://biology-forums.com/gallery/47/medium_33_31_08_11_2_12_19_16181010.jpeg)
![Muskox populations remain in the Arctic all year, though they migrate to higher elevations in the wi](https://biology-forums.com/gallery/47/medium_33_22_09_11_9_37_27_1803362.jpeg)