|
|
Did you know?
Vaccines prevent between 2.5 and 4 million deaths every year.
Did you know?
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.
Did you know?
Illicit drug use costs the United States approximately $181 billion every year.
Did you know?
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.
Did you know?
On average, the stomach produces 2 L of hydrochloric acid per day.