DNA replicates before cell division, duplicating chromosomes. This occurs during S stage of interphase! Now each chromosome has two identical double helical models.
        
             
        
        
        
Answer: It depends on if your only talking about plants if so the answer is coal.
Explanation: The reason being because coal only forms from the compaction of dead plants whereas petroleum forms from compacted plants and animals.
 
        
             
        
        
        
B- Enzymes act as catalysts to speed up chemical reactions