Even when germs try to sneak in, your body is not helpless. You have your very own defense team working around the clock to keep you safe. You do not even have to think about it, because your body does this job automatically.

Your first guard is your skin. Skin wraps around your whole body like a strong, bendy wall that most germs cannot get through. That is one reason a clean, unbroken layer of skin helps keep you healthy.

But walls sometimes get a gap, like when you get a cut or a scrape. Right away, sticky blood rushes in and dries into a scab, sealing the hole so germs cannot climb inside.

Inside you, your blood carries tiny germ-fighting cells called white blood cells. These cells are like brave little soldiers that swim through your body, hunt down germs, and gobble them up before they can spread.

Sometimes the fight makes you feel warm or gives you a fever. A fever is your body turning up the heat on purpose, because many germs do not like the heat and get weaker. Rest and water help your team win faster.

You can help your defense team every day. Sleeping enough, eating fruits and vegetables, and washing your hands all give your soldiers more strength to protect you. You and your body are teammates.