|
|
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.
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.
According to research, pregnant women tend to eat more if carrying a baby boy. Male fetuses may secrete a chemical that stimulates their mothers to step up her energy intake.
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.
![The path of blood flow through the chambers of the left and right side of the heart, including the v](https://biology-forums.com/gallery/47/medium_14755_10_09_12_7_22_09_8519715.jpeg)
![Skin structure, including the three layers of the skin and the accessory organs: sweat gland, sebace](https://biology-forums.com/gallery/47/medium_14755_16_09_12_5_57_13_87522080.jpeg)