|
|
IgA antibodies protect body surfaces exposed to outside foreign substances. IgG antibodies are found in all body fluids. IgM antibodies are the first type of antibody made in response to an infection. IgE antibody levels are often high in people with allergies. IgD antibodies are found in tissues lining the abdomen and chest.
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.
It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.
![Like most world-changing inventions, the printing press of fifteenth-century Europe took advantage o](https://biology-forums.com/gallery/47/medium_6_15_08_15_11_36_37_22214776.jpeg)
![Edward Bellamy, author of the utopian novel Looking Backward (1888) Bellamy’s socialism worried many](https://biology-forums.com/gallery/47/medium_27_24_08_15_1_27_04_223942387.jpeg)
![At breakfast, a middle-class husband sits absorbed in the newspaper and the public affairs of the da](https://biology-forums.com/gallery/47/medium_6_24_08_15_12_36_52_224132038.jpeg)