Sometimes people worry about the germs that they come into contact with daily. In fact, most people would be surprised to learn just how many microbes actually inhabit a human's body at any given time, in addition to the larger visitors that come around occasionally. Such natural species that regularly come into contact with our bodies include mites, lice, yeast, and fungus, just to name a few. We are, in fact, an ecosystem much like a rainforest is to the natural flora and fauna that call it home.
Lice, or nits, are particularly horrible to even think about. To learn that one's child has been found in school with head lice can cause trauma and shame. People think that having lice is a symptom of being unclean, although one can be infected by contact with somebody else who has them. Although lice are not that common in general circles, children can easily acquire them just because of their close contact with other children at school or play. Some large cities host high-priced nitpickers who make a living removing head lice from children.
Mites on the human body are much more common, and cleanliness does not eliminate the chance of having them. They are also microscopic, so they are invisible to the naked eye. There are a number of different species of mites, two of which have the human face as their natural habitat, particularly the skin of the forehead. Others are very content among human hair, living among the follicles of the eyelashes, eyebrows, and scalp hair.
Not all such inhabitants are harmful. In fact, even the annoying mite lives on dead skin cells, actually doing us a favor by removing them. The dreaded dust mite, for example, blamed for causing allergies, removes dead skin from bed coverings. And harmless bacteria often keep potentially harmful bacteria from being able to survive. So people should not try to eliminate mites from their bodies, although some have tried. Some sufferers of obsessive/compulsive disorder have scrubbed themselves raw trying to eliminate all scavengers from their bodies, only to damage their skin, and all to no avail.
Certain types of yeast also regularly live on the human body, Sometimes causing annoyances. One common type lives on the oil produced in the skin of the face or scalp, causing a condition known as pityriasis versicolor, which is a scaling and discoloration of the skin.
Ailments such as athlete's foot are caused by a fungus that grows in warm, moist conditions. To avoid them or avoid a recurrence, patients are encouraged to keep their feet dry and cool, which of course may not be easy, depending on one's work or personal habits. Ringworm is also a fungus acquired by contact with keratin-rich soil in many parts of the world.
Besides the tiny inhabitants, we are also regularly harassed by insects that feed off of our bodies, like mosquitoes, ticks, and fleas, which sometimes deposit harmful illnesses at the same time they probe the skin for the blood on which they live. Mosquitoes have been known to cause malaria and yellow fever, as well as encephalitis. Fleas have transmitted bubonic plague, and ticks have caused lyme disease.
Just like a river, an ocean, a rainforest, or any other ecological wonder in which numerous species survive, feeding upon other inhabitants, our bodies are natural providers of nutrition and life for various small and microscopic species.
12. The author's main point is
13. The author infers that lice and mites are different in that
14. The word "shame" in the second paragraph is closest in meaning to
15. The word "their" in the second paragraph refers to
16. The word "Others" in the third paragraph refers to
17. The author indicates that lice are also known as
18. The author indicates that a nitpicker is
19. The author infers that
20. What does the author mean by the statement "Not all such inhabitants are harmful" at the beginning of the fourth paragraph?