|
|
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).
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.
To prove that stomach ulcers were caused by bacteria and not by stress, a researcher consumed an entire laboratory beaker full of bacterial culture. After this, he did indeed develop stomach ulcers, and won the Nobel Prize for his discovery.
Symptoms of kidney problems include a loss of appetite, back pain (which may be sudden and intense), chills, abdominal pain, fluid retention, nausea, the urge to urinate, vomiting, and fever.
During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).