1. No credible source
2. Check if its a biased answer
3. Examine evidence
 
        
             
        
        
        
B natural changes allow for greater biodiversity
        
             
        
        
        
Cells need to reproduce for growth, repair, or replacements. Cells divide whenever a tissue / organ / organism is growing or needs repair.
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Genetic variation<span> is essential for </span>natural selection<span> because </span>natural selection can only increase or decrease frequency of alleles that already exist in the population.Genetic variation<span> is caused by: mutation
i pulled this off of the site i got the information from i hope this helps you out if not sorry
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The idea that all living things are composed of cells and that all cells come from other cells defines the cell theory. 
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