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Author Question: In network economics, the value of a commercial software vendor's software products: A) increases ... (Read 138 times) |
The horizontal fraction bar was introduced by the Arabs.
All patients with hyperparathyroidism will develop osteoporosis. The parathyroid glands maintain blood calcium within the normal range. All patients with this disease will continue to lose calcium from their bones every day, and there is no way to prevent the development of osteoporosis as a result.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
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).