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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.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
Blood is approximately twice as thick as water because of the cells and other components found in it.
According to the Migraine Research Foundation, migraines are the third most prevalent illness in the world. Women are most affected (18%), followed by children of both sexes (10%), and men (6%).
In the United States, an estimated 50 million unnecessary antibiotics are prescribed for viral respiratory infections.