- Grade 11 and 12 Mathematics (Moderator: geoffrey)
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- Grade 11 and 12 Mathematics (Moderator: geoffrey)
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.
There are 20 feet of blood vessels in each square inch of human skin.
Drug abusers experience the following scenario: The pleasure given by their drug (or drugs) of choice is so strong that it is difficult to eradicate even after years of staying away from the substances involved. Certain triggers may cause a drug abuser to relapse. Research shows that long-term drug abuse results in significant changes in brain function that persist long after an individual stops using drugs. It is most important to realize that the same is true of not just illegal substances but alcohol and tobacco as well.
Drugs are in development that may cure asthma and hay fever once and for all. They target leukotrienes, which are known to cause tightening of the air passages in the lungs and increase mucus productions in nasal passages.
Pregnant women usually experience a heightened sense of smell beginning late in the first trimester. Some experts call this the body's way of protecting a pregnant woman from foods that are unsafe for the fetus.
![Lungs: RUL = Right Upper Lobe, RML = Right Middle Lobe, RLL = Right Lower Lobe, LUL = Left Upper Lob](https://biology-forums.com/gallery/47/medium_2137_21_07_12_5_27_30.jpeg)
![GI series. (a) Upper GI series begins with a barium swallow, barium shake, or barium meal. (b) Lower](https://biology-forums.com/gallery/47/medium_14755_26_10_12_5_23_55_96931000.jpeg)