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Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.
Did you know?
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
Did you know?
There are more nerve cells in one human brain than there are stars in the Milky Way.
Did you know?
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.

