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Author Question: Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are ... (Read 71 times) |
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.
Coca-Cola originally used coca leaves and caffeine from the African kola nut. It was advertised as a therapeutic agent and "pickerupper." Eventually, its formulation was changed, and the coca leaves were removed because of the effects of regulation on cocaine-related products.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
The term bacteria was devised in the 19th century by German biologist Ferdinand Cohn. He based it on the Greek word "bakterion" meaning a small rod or staff. Cohn is considered to be the father of modern bacteriology.