|
Author Question: Many freedmen saw emancipation as the opportunity to a. punish their former masters. b. take ... (Read 221 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.
The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
There are more nerve cells in one human brain than there are stars in the Milky Way.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.