|
Author Question: As oil prices increase, it becomes more economical to extract oil from sources like tar sands. ... (Read 54 times) |
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
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.
Prostaglandins were first isolated from human semen in Sweden in the 1930s. They were so named because the researcher thought that they came from the prostate gland. In fact, prostaglandins exist and are synthesized in almost every cell of the body.
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.
There are 60,000 miles of blood vessels in every adult human.