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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.

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Symptoms of kidney problems include a loss of appetite, back pain (which may be sudden and intense), chills, abdominal pain, fluid retention, nausea, the urge to urinate, vomiting, and fever.

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This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.

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When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.

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The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.

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Primates in the New World tend to be small-bodied compared to those elsewhere. Primates in the New World tend to be small-bodied compared to those elsewhere.
A second jetliner approaches the south tower of the World Trade Center on September 11, 2001. The no A second jetliner approaches the south tower of the World Trade Center on September 11, 2001. The no
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Video: Methods of carbon dioxide transport - carbaminohemoglobin and bicarbonate ions

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