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Author Question: By which school year did all states test reading and mathematics annually in grades 3-11? (Read 49 times) |
The horizontal fraction bar was introduced by the Arabs.
Studies show that systolic blood pressure can be significantly lowered by taking statins. In fact, the higher the patient's baseline blood pressure, the greater the effect of statins on his or her blood pressure.
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.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.