Today’s Wonder of the Day was inspired by camel from AL. camel Wonders, “How do bacteria breathe?” Thanks for WONDERing with us, camel!

You wake up in the morning and immediately know something is wrong. Your throat is sore and your head hurts something fierce. The minute you move, you start to cough. Just standing up causes your stomach to rumble and threaten something worse. Simple movements take effort and you're really hot.

It doesn't take you long to figure out what's wrong: you're sick. Instead of heading to school, you'll be heading back to bed. But first, you need to check with your parents. This set of symptoms could mean you're headed to see the doctor, too.

If you've been to the doctor many times in recent years, you've probably been given medicine on many occasions that helps you to get better. Sometimes, though, the doctor might say that there isn't any medicine to treat your illness. In those cases, you just need to rest, drink plenty of fluids, and use over-the-counter medications to help alleviate some of the symptoms you may be experiencing.

If you've ever WONDERed why you sometimes get a prescription for medicine at the doctor and other times you don't, it probably has to do with the various causes of illnesses. While germs are usually to blame, it depends upon exactly which type of germs you're dealing with.

Germs mostly fall into four main types: bacteria, viruses, fungi, and protozoa. The most common germs that cause us to be sick are bacteria and viruses. Although they're both germs, they're very different creatures that have to be battled in different ways.

Bacteria are tiny organisms that consist of just one cell. They take nutrients from the environment around wherever they happen to be, which is sometimes inside the human body. When they invade the body, bacteria can cause a multitude of different types of infections that make us sick.

Some common infections you may have experienced before include tonsillitis, strep throat, cavities, and ear infections. When doctors determine that the source of an infection is bacteria, they usually prescribe an antibiotic to fight the bacterial germs.

Not all bacteria are bad for us, though. Some bacteria are helpful and necessary for us to stay healthy. For example, there are good bacteria that live in our intestines. They help keep our bodies in balance by aiding in digestion. Not only can they help our bodies make better use of the nutrients in our food, they can also help turn what's left over into waste.

Bacteria can grow outside the human body, if necessary. Viruses, on the other hand, need to be inside living cells to grow and reproduce. Viruses are even smaller than bacteria. If they're not inside a human being, plant, or animal, they won't survive for long.

When viruses get inside of a living thing (called a host), they invade and take over cells, using them to reproduce themselves and spread throughout the host. Viruses can cause a variety of illnesses, including chickenpox, measles, and the flu. Unlike bacteria, there are no helpful viruses for your body.

If you have an illness caused by a virus, you often have to let the illness run its course. Antibiotics rarely work against viruses like they do against bacteria. The body's own natural defenses will usually overcome viruses if given enough time. While waiting for the body to fight viruses, it's important to drink lots of fluids, get plenty of rest, and treat whatever symptoms you can with over-the-counter medicines.

So when you have a whole host of symptoms and are quite sick, a visit to the doctor's office may or may not result in a prescription for medicine that will kill the germs causing your illness. Of course, a doctor's job is never easy, because some illnesses, like pneumonia, meningitis, and diarrhea, can sometimes be caused by bacteria and other times by viruses!

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