When you think about b l o o d, the first characteristic that probably comes to mind is its color. B l o o d that has just taken up oxygen in the lungs is bright red, and b l o o d that has released oxygen in the tissues is a darker red. This is because hemoglobin is a pigment that changes color, depending upon the degree of oxygen saturation.
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When you think about b l o o d, the first characteristic that probably comes to mind is its color. B l o o d that has just taken up oxygen in the lungs is bright red, and b l o o d that has released oxygen in the tissues is a darker red. This is because hemoglobin is a pigment that changes color, depending upon the degree of oxygen saturation.