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Many of the drugs used by neuroscientists are derived from toxic plants and venomous animals (such as snakes, spiders, snails, and puffer fish).
Most fungi that pathogenically affect humans live in soil. If a person is not healthy, has an open wound, or is immunocompromised, a fungal infection can be very aggressive.
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).
Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.
Hyperthyroidism leads to an increased rate of metabolism and affects about 1% of women but only 0.1% of men. For most people, this increased metabolic rate causes the thyroid gland to become enlarged (known as a goiter).