|
Author Question: Jake walks a classmate to her car after class and decides, based on the car's make and model, that ... (Read 912 times) |
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
According to the National Institute of Environmental Health Sciences, lung disease is the third leading killer in the United States, responsible for one in seven deaths. It is the leading cause of death among infants under the age of one year.
Asthma is the most common chronic childhood disease in the world. Most children who develop asthma have symptoms before they are 5 years old.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.