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The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).
Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.
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.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.