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Did you know?
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
Did you know?
Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.
Did you know?
Thyroid conditions may make getting pregnant impossible.
Did you know?
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
Did you know?
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.