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There are 60,000 miles of blood vessels in every adult human.
Urine turns bright yellow if larger than normal amounts of certain substances are consumed; one of these substances is asparagus.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
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 cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
![In The Gross Clinic (1875), by Thomas Eakins, Professor Samuel Gross’s team of surgeons cuts through](https://biology-forums.com/gallery/47/medium_376716_26_08_15_11_14_05_22440772.jpeg)
![A parade for Grover Cleveland in Chicago in 1892, by John Klir. Music, mirth, real drama—a president](https://biology-forums.com/gallery/47/medium_376716_26_08_15_11_16_35_22443872.jpeg)