|
|
The word drug comes from the Dutch word droog (meaning "dry"). For centuries, most drugs came from dried plants, hence the name.
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.
Of the estimated 2 million heroin users in the United States, 600,000–800,000 are considered hardcore addicts. Heroin addiction is considered to be one of the hardest addictions to recover from.
After 5 years of being diagnosed with rheumatoid arthritis, one every three patients will no longer be able to work.
The modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).
![Large size can provide a refuge from predators. While young African elephants may be vulnerable to p](https://biology-forums.com/gallery/47/medium_33_17_02_12_5_35_26_19681934.jpeg)
![(a) Feeding by bear on salmon results in large allochthonous inputs of nutrients into (b) the forest](https://biology-forums.com/gallery/47/medium_33_17_02_12_7_02_16_2035460.jpeg)
![Several species of squirrels have melanistic phases. In large parts of United States and Canada, the](https://biology-forums.com/gallery/47/medium_27692_23_04_12_3_37_08.jpeg)