The disadvantages of smoking are so many to our health, but still some people enjoy it. Smoking contains 4000 chemical substance and about 200 among them are danger for our life, such as cadmium, tolucne, hexamine, methanol, carbon monoxide, DDT, acetic acid, acetone, formaldehyde, ammonia, stearic acid, arsenic, hydrogen cyanide, nicotine, ethanol, methane, butane, tar, etc.
The main poisons in smoking are nicotine, tar, and carbon monoxide.
Nicotine is a nerve poison that usually used as a raw material for many kinds of insecticide. In low concentration, this substance can make addiction effect. Nicotine has limited carcinogen ability that decrease body immunity against cancer.
Tar will disturb revive channels and cause cough or sultry. A pile of tar in our body will cause cancer.
Carbon monoxide also has bad impact to blood vessels. It bound easier to hemoglobin than oxygen do. That's why smoker often feel in weak condition.
March 05, 2009
October 17, 2008
WHY SAVE RAIN FORESTS ?
Located mostly around the equator, more than half of the tropical rain forests have already disappeared in the past fifty years. Dozens of environmental groups have raised millions of dollars to save these forests and have sent experts to help. Yet there are still some people who say, "Why save rain forests?" Well, these people would not ask such a question if only they knew that rain forests contribute a great deal to the medical industry, to the balancing of global weather patterns and to the prevention of soil erosion as well as pollution.
Scientists have learned that over 1,300 rain forest plants in South America have medicinal value. So far less than 10% of the plant and animal species in the world's rain forests have been studied for their possible medical benefits - and of those that have been studied, about 1% proved to contain potential value for the treatment of cancer.
But the value of tropical rain forests goes beyond medicine. These forests have a critical impact on global weather patterns. Their vegetation absorbs an enormous quantity of the sun's heat, thus minimizing the change in wind and rainfall patterns around the world. This vegetation also absorbs huge amounts of carbon dioxide. Carbon dioxide that is released into the air contributes to the greenhouse effect or global warming.
Rain forests also prevent soil erosion and pollution. The roots of the vegetation in rain forests help keep the soil safe from both water and wind erosion in areas that could be damaged by floods and strong winds. Furthermore, the vegetation in rain forests purifies the air by absorbing carbon dioxide. So, rain forests also control air pollution.
In conclusion, our lives would be different without rain forests. The medical industry would have difficulty looking for a breakthrough in fighting diseases. Land soil would lose its fertility, and pollution would get worse. To prevent these things from happening, we must really help save rain forests, and we must start now!
Adapted from: Stempleski, Susan, Focus on Environment, Regents/Prentice Hall, 1993
Scientists have learned that over 1,300 rain forest plants in South America have medicinal value. So far less than 10% of the plant and animal species in the world's rain forests have been studied for their possible medical benefits - and of those that have been studied, about 1% proved to contain potential value for the treatment of cancer.
But the value of tropical rain forests goes beyond medicine. These forests have a critical impact on global weather patterns. Their vegetation absorbs an enormous quantity of the sun's heat, thus minimizing the change in wind and rainfall patterns around the world. This vegetation also absorbs huge amounts of carbon dioxide. Carbon dioxide that is released into the air contributes to the greenhouse effect or global warming.
Rain forests also prevent soil erosion and pollution. The roots of the vegetation in rain forests help keep the soil safe from both water and wind erosion in areas that could be damaged by floods and strong winds. Furthermore, the vegetation in rain forests purifies the air by absorbing carbon dioxide. So, rain forests also control air pollution.
In conclusion, our lives would be different without rain forests. The medical industry would have difficulty looking for a breakthrough in fighting diseases. Land soil would lose its fertility, and pollution would get worse. To prevent these things from happening, we must really help save rain forests, and we must start now!
Adapted from: Stempleski, Susan, Focus on Environment, Regents/Prentice Hall, 1993
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