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Author Question: Which is the first sign of puberty in a female? a. breast buds b. pubic hair c. underarm hair ... (Read 124 times) |
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
During pregnancy, a woman is more likely to experience bleeding gums and nosebleeds caused by hormonal changes that increase blood flow to the mouth and nose.
Earwax has antimicrobial properties that reduce the viability of bacteria and fungus in the human ear.