Answer:
i don't know
Explanation:
I'm just trying to get points
 
        
             
        
        
        
Cancer cells multiply rapidly and normal cells don't.
        
             
        
        
        
Answer:
Mitochondrial DNA.
Explanation:
Mitochondria is known as the power house of the cell and one of the important organelle responsible for the production of energy. Mitochondria contains its own DNA.
To understand the maternal ancestor history, the mitochondria DNA  must be studied. The mitochondria is solely obtained from the mother as the egg contains large amount of cytoplasm that contains mitochondria. The mitochondria can never be inherited from paternal origin as the sperm contains few amount of cytoplasm and mitochondria. 
Thus, the answer is mitochondrial DNA.