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You can't live without your skin. But skin does much more than keep us alive, and much more than most people probably suspect: It can detect danger, ward off infections, and even help us smell.

"Your skin is powerful in so many ways," said New York City dermatologist Doris Day. "It's a remarkable, independent organ, although people don't always respect it as such."

Here are nine reasons why you should:

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Skin can help diagnose disease:

"Skin is a very powerful reflector of your overall health and well-being," Day said. "If you have a liver or kidney disease, diabetes, heart issue -- it has a way of showing up in skin."

Indeed, Rehana Ahmed, a dermatologist in Edina, Minn., said she has often diagnosed thyroid disease by examining patients' eyebrows, and once by looking at leg hair. "About a third of the eyebrow can stop growing" because the body is conserving hormones used both for hair growth and thyroid function, she said. The skin can also offer clues to depression and Obsessive-Compulsive Disorder, Day said.

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It helps you smell:

One of the most recent studies on skin shows that olfactory receptors are found in the epidermis. In other words, according to new research, your skin can actually smell itself.

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It stretches:

Ahmed, who is nine months pregnant, has experienced this first-hand. "If it stretched that much overnight, it would tear," she said. "But it has elastic fibers that (slowly) allow us to stretch -- and also to bounce back."

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It keeps you cool:

When your body warms up, your blood vessels dilate and your skin starts flushing, Ahmed said. Water escapes as sweat.

"Sweating is the way to cool yourself quickly," Ahmed said. "You can sweat up to three gallons a day. And if you don't sweat, you can overheat."

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It's a powerful communicator:

"When you're flushed red, that's a warning to your adversaries that you're on guard," Day said. "And when you turn white or pale, that shows you’re scared."

When you put your best face forward, that conveys that you're balanced, stable, and happy, she said. "The color and tone of your skin can convey a lot of different emotions."

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It helps prevent further sun damage:

When UV light damages your DNA, it shows up as a sunburn or a tan. Although it's far healthier to prevent DNA damage, which can lead to cancer, in the first place, tanning helps the situation from getting even worse.

"The tan comes as a response to the DNA damage which prompts the cells to secrete more melanin which darkens the skin," said dermatological surgeon Jerry Brewer of the Mayo Clinic. "Dark skin is more protective to the DNA than white skin, so it is an effort to decrease the causalities the next time a UV insult arrives."

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It fights infection:

The skin has its own immune system and acts as the body’s first defense against the outside world, Day said. Cells in the epidermis, called Langerhans cells, warn the body when it comes into contact with viruses or other sources of infection. Thankfully, your skin cells also help prevent bacteria and mold from growing, Ahmed said.