|
|
Only 12 hours after an egg cell is fertilized by a sperm cell, the egg cell starts to divide. As it continues to divide, it moves along the fallopian tube toward the uterus at about 1 inch per day.
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.
Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing for mass cultivation and purification from bacterial cultures.
Approximately 500,000 babies are born each year in the United States to teenage mothers.
The first successful kidney transplant was performed in 1954 and occurred in Boston. A kidney from an identical twin was transplanted into his dying brother's body and was not rejected because it did not appear foreign to his body.
![Blocked at every turn by congressional Republicans who hated him, President Obama turned to techniqu](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_37_17_22182952.png)
![In 2013, Americans learned that the federal government massively surveys their phone calls and e-mai](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_46_35_221931656.png)
![A vigorous-looking Franklin D. Roosevelt campaigns for the presidency in 1932. His vice-presidential](https://biology-forums.com/gallery/47/medium_568533_22_08_16_12_25_27_237311385.jpeg)