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Author Question: In a contest, two tractors pull two identical blocks of stone the same distance over identical ... (Read 3792 times) |
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.
Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.