<u>Answer:
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When the outer electron shell is full in an element, this creates a Noble gas.
<u>Explanation</u>:
Noble gases are the elements that belong to group 18 in the periodic table.  Noble gases are also called as inert gases. The outermost shell of the noble gases are fully filled by electrons. Due to this the noble gases don’t react with any other elements and remain isolated.
There are 6 noble gases in the periodic table. They are helium (He), Argon (Ar), Neon (Ne) Krypton (Kr), Radon (Rn) and Xenon (Xe). Noble gases conduct electricity. They are fluorescent, odorless and colorless. Noble gases are used a maintain stable elements in a constant and safe environment.
 
        
             
        
        
        
A good passing current is a small wave for example. 
        
             
        
        
        
Answer:
The answer is B.
Explanation:
When you skin your knee,  cells divide to replace old, dead, or damaged cells. 
 
        
                    
             
        
        
        
Ans. 
Genetic codes provide information for the protein synthesis as each code specifically codes a particular amino acid that gets joined in polypeptide chain during the process of translation. 
Each genetic code is three letter code, made up of three nitrogenous bases. There are four different bases in DNA or RNA that make sixty four codes with different combinations, out of which sixty one code for amino acids and three act as stop codons.
Thus, nitrogenous bases are important in preserving the genetic codes.