|
|
Did you know?
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.
Did you know?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Did you know?
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Did you know?
The longest a person has survived after a heart transplant is 24 years.
Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.