|
|
Only 12 hours after an egg cell is fertilized by a sperm cell, the egg cell starts to divide. As it continues to divide, it moves along the fallopian tube toward the uterus at about 1 inch per day.
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.
The word drug comes from the Dutch word droog (meaning "dry"). For centuries, most drugs came from dried plants, hence the name.
The senior population grows every year. Seniors older than 65 years of age now comprise more than 13% of the total population. However, women outlive men. In the 85-and-over age group, there are only 45 men to every 100 women.
Illicit drug use costs the United States approximately $181 billion every year.
![An example of color blindness test. A person with red-green color blindness would not be able to dis](https://biology-forums.com/gallery/47/medium_14755_27_08_12_12_28_10_82021889.jpeg)
![The explosion of the Maine in Havana harbor, killing 260 men, caused much speculation in the newspap](https://biology-forums.com/gallery/47/medium_6_02_03_16_7_45_21_234021930.jpeg)