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As the western states of America were settled, pioneers often had to drink rancid water from ponds and other sources. This often resulted in chronic diarrhea, causing many cases of dehydration and death that could have been avoided if clean water had been available.
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.
Drying your hands with a paper towel will reduce the bacterial count on your hands by 45–60%.
Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.
The familiar sounds of your heart are made by the heart's valves as they open and close.