Telomeres are protective sequences of nucleotides found at the ends of chromosomes,Which become shorter every time a cell divides.
A gradual degeneration of an organism occurs, resulting in ageing.
However, some cells are able to replenish their telomeres using the enzyme telomerase. 
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The answer is <span>2 can be made by the animal's body from other substances.
Both essential and nonessential amino acids have essential roles in the organism. Nonessential amino acids got their name because they are not an essential part of the diet. The main difference between these two groups of amino acid is that essential amino acids cannot be made by the animal's body and must be ingested in the diet unlike the nonessential amino acid which can be made by the animal's body.</span>
        
             
        
        
        
Answer:
The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life".
Explanation:
 
        
             
        
        
        
The answer u r looking for is- A, all of the above. Hope I’ve helped ;)