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Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.
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.
A headache when you wake up in the morning is indicative of sinusitis. Other symptoms of sinusitis can include fever, weakness, tiredness, a cough that may be more severe at night, and a runny nose or nasal congestion.
Blood is approximately twice as thick as water because of the cells and other components found in it.