Give Reasons : Bone cancer spreads largely between Japanese rice farmers.
Ø Radioactive Sr 90 from fallout pollutes rice. Sr 90 ingested with rice replaces calcium in the bone causing bone cancer.
Noise pollution 1. Sources: aero planes Radio & T.V. Transport means Factory machines Air conditioning
2. Sound intensity: is measured by a universal unit called decible. The human ear responds to sound range within 130 decibels.
Controlling sound pollution: 1-Decrease sound intensity of the source by using quieter machines. Move airports away from inhabited places. 2-Machines are placed on rubber bases to decrease their movement or are provided by shock absorbers. 3. Factory workers should use ear protective covers.
Nations can be classified into two groups: 1. Developed countries: such as the European countries which have improved health care so death rate decreased. The natural rate of birth is declining which makes the population stable. 2. Developing countries such as Egypt have a high birth rate & low death rate which result in natural increase in population. In Latin America the rapid increase in population is not a problem because their natural recourses need working hands. Solution of the population problem in Egypt : 1. Emigration (Talented , highly qualified human resources head to Europe &USA. Egyptians who earn a high income in Arab countries return to Egypt & therefore the prices of land & houses to rise.) 2. Birth control. 3. Economic reform. v Food problem in Egypt is caused by the increase of population without a similar increase in cultivated land & animal production.
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