|
|
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Approximately 500,000 babies are born each year in the United States to teenage mothers.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Though methadone is often used to treat dependency on other opioids, the drug itself can be abused. Crushing or snorting methadone can achieve the opiate "rush" desired by addicts. Improper use such as these can lead to a dangerous dependency on methadone. This drug now accounts for nearly one-third of opioid-related deaths.
Many people have small pouches in their colons that bulge outward through weak spots. Each pouch is called a diverticulum. About 10% of Americans older than age 40 years have diverticulosis, which, when the pouches become infected or inflamed, is called diverticulitis. The main cause of diverticular disease is a low-fiber diet.
![Three Tasmanian devils feeding. Eating is a social event for the Tasmanian devil, and groups of 2 to](https://biology-forums.com/gallery/47/medium_27692_23_04_12_4_15_26.jpeg)
![Maps are important tools in political science as they help us see relationships between politics and](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_33_48_221781179.png)