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Author Question: Computer viruses first appeared in the early __________. A. 1960s B. 1970s C. 1980s D. ... (Read 55 times) |
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.
Asthma-like symptoms were first recorded about 3,500 years ago in Egypt. The first manuscript specifically written about asthma was in the year 1190, describing a condition characterized by sudden breathlessness. The treatments listed in this manuscript include chicken soup, herbs, and sexual abstinence.
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).
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.