- Grade 11 and 12 Mathematics (Moderator: geoffrey)
|
|
- Grade 11 and 12 Mathematics (Moderator: geoffrey)
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
There are 20 feet of blood vessels in each square inch of human skin.
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.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
In 1864, the first barbiturate (barbituric acid) was synthesized.