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Did you know?
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Did you know?
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.
Did you know?
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
Did you know?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Did you know?
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.