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Did you know?
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Did you know?
More than 50% of American adults have oral herpes, which is commonly known as "cold sores" or "fever blisters." The herpes virus can be active on the skin surface without showing any signs or causing any symptoms.
Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Did you know?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.