How do classification systems change over time?

When scientist find new species, that may have to change classification systems in order to accommodate them. DNA let us find more about evolutionary relationships, meaning animals we thought were closely related may not be. Basically summing it up - scientists have to change the way they classify them because animal, or other things turn out not being closely related making them unsure and changing. 

Yes it is hereditary because of the penis

C) to ensure each new cell has an exact copy of the dna