Central Nervous System:

In the Central Nervous System (CNS)  there are two components in the CNS called the 

• Brain
• Spinal Cord

Radioactive pollution causes certain forms of mental retardation, Down's syndrome and other mental disorders . Sometimes exposure to radioactive elements kills a particular cell in the fetus that would later form the right half of the brain resulting in malformation of the brain and increased evidence of brain tumors. 

Definitions: 

Down's Syndrome: It is a disorder by having an extra 21 st chromosome, this results in mental retardation, having a flat face etc. 

Brain Tumor:  it's a tumor that occurs in the brain.

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