D. transportation accidents.
        
             
        
        
        
Answer:
I think its the third one :)
Explanation:
hope this helped :))
 
        
             
        
        
        
Answer:
23 chromosomes
Unlike all the other cells in a human body which are diploid, human sex cells are haploid. That means that both sperm cells and ova are haploid; containing only 23 chromosomes.
Explanation:
have a good day!
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It spread by person to person