|
|
Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.
Amoebae are the simplest type of protozoans, and are characterized by a feeding and dividing trophozoite stage that moves by temporary extensions called pseudopodia or false feet.
The word drug comes from the Dutch word droog (meaning "dry"). For centuries, most drugs came from dried plants, hence the name.
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.
Of the estimated 2 million heroin users in the United States, 600,000–800,000 are considered hardcore addicts. Heroin addiction is considered to be one of the hardest addictions to recover from.
![Magnetic resonance imaging (MRI). The MRI lab includes the scanning instrument and a computer statio](https://biology-forums.com/gallery/47/medium_14755_14_10_12_6_49_35_9415513.jpeg)
![Urinary catheterization. The procedure involves the insertion of a flexible tube, or catheter, throu](https://biology-forums.com/gallery/47/medium_14755_26_10_12_5_21_07_96742390.jpeg)