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Did you know?
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.
Did you know?
Amoebae are the simplest type of protozoans, and are characterized by a feeding and dividing trophozoite stage that moves by temporary extensions called pseudopodia or false feet.
Did you know?
There are approximately 3 million unintended pregnancies in the United States each year.
Did you know?
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
Did you know?
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.