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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.

Sound intensity Effect
More than 80 decibels for several hours daily. -Nervous tension, complete deafness may occur.
Sudden uproar of a jet plane or great explosion -Nervous disorder - High blood pressure
100 decibels -Experimental rats became ill, due to the high percentage of ammonia in their blood.
175 decibels the rats died

 
 
Thunder 120 decibel Jet planes 110 decibel Aero planes 100 decibel Crowded areas 70 decibel Quite home 15 decibel Whispers 10 decibel  

 

 


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.

 

 

 

The primitive stage The transitional stage The stable stage
High birth & death rates which lead to low growth rate. Health care reduced death rate & increased birth rate. High growth rate. Death rate is slightly higher than birth rate & therefore population is declining.
This stage occurred thousands of years ago Egypt exists in this stage. Europe passed the transitional stage & exists in this stage now.

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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