Genetic variation<span> occurs </span>mainly<span> through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction</span>
        
                    
             
        
        
        
Over population if i recall correctly
        
             
        
        
        
Answer:
Hey mate.....
Explanation:
This is ur answer.....
---> Sunlight, Water and Carbon dioxide 
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Yes, but it's not technically sperm yet.