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In 1864, the first barbiturate (barbituric acid) was synthesized.
Multiple experimental evidences have confirmed that at the molecular level, cancer is caused by lesions in cellular DNA.
An identified risk factor for osteoporosis is the intake of excessive amounts of vitamin A. Dietary intake of approximately double the recommended daily amount of vitamin A, by women, has been shown to reduce bone mineral density and increase the chances for hip fractures compared with women who consumed the recommended daily amount (or less) of vitamin A.
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
![Retrograde pyelography (RP). Note the contrasting of the renal calyces, ureters, and bladder followi](https://biology-forums.com/gallery/47/medium_14755_05_10_12_4_17_11_9293297.jpeg)
![Retrograde pyelogram. A contrast medium is injected into the ureter using a cystoscope, and the X-ra](https://biology-forums.com/gallery/47/medium_14755_26_10_12_5_21_06_9671618.jpeg)