|
|
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.
About one in five American adults and teenagers have had a genital herpes infection—and most of them don't know it. People with genital herpes have at least twice the risk of becoming infected with HIV if exposed to it than those people who do not have genital herpes.
The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.
People with alcoholism are at a much greater risk of malnutrition than are other people and usually exhibit low levels of most vitamins (especially folic acid). This is because alcohol often takes the place of 50% of their daily intake of calories, with little nutritional value contained in it.
Essential fatty acids have been shown to be effective against ulcers, asthma, dental cavities, and skin disorders such as acne.
![The conduction system of the heart; traces the path of the electrical impulse that stimulates the he](https://biology-forums.com/gallery/47/medium_14755_10_09_12_7_22_09_85202259.jpeg)
![How lenses correct visual problems: (A) emmetropia; (B) myopia; (C) hyperopia; (D) corrected myopia; ...](https://biology-forums.com/gallery/47/medium_665046_10_03_17_10_10_22_268001454.jpeg)