A、Preventing bacteria and harmful substances from entering into the body. B、Regulating the temperature of the body. C、Serving as

The intact skin cannot protect us against sharp objects, but it can prevent bacteria and harmful substances from entering into our bodies, and help the process of evaporation. A break of the skin may be followed by serious infection.
    The regulation of body temperature is also a very important function of the skin. The skin forms a large surface for radiating body heat to the air. When the blood vessels enlarge, more blood is brought to the surface so that heat can be sent out into the air. The evaporation of sweat from the surface of the body also helps to cool the body. As is the case with so many body functions, the matter of temperature regulation is complex and involves several parts of the body, including certain centers in the brain.
    A child loses heat faster than does an adult since a higher proportion of the body is skin surface , and thus relatively more area is exposed. Therefore, it is important to prevent undue exposure to the elements in the case of infants and small children. The elderly do not produce heat in the body so easily nor to so great an extent; therefore they also should be protected against cold.
    A most important function of the skin is in obtaining information from the environment. Because of the many receptors for pain, touch, pressure and temperature, which are located mostly in the skin, it may be regarded as one of the chief sensory organs of the body. Many of the reflexes which make it possible for the human being to adjust himself to the environment begin as sensory impulses from the skin. Here, too, the skin works in cooperation with the brain and to make these important functions possible. 26. Which of the functions of the skin is NOT mentioned in the passage?
27. Which is not true about the matter of temperature regulation?
28. Why does a child lose heat faster than an adult?
29. According to the passage, what information can NOT be obtained by skin?
30. Which is the most important function of the skin?