"changes or variations within a species exist,no one is questioning that fact
what is not fact,is one species does not turn into another species...."
Incorrect. Species do spontaneously and/or adaptively speciate. Numerous counts of concrete evidence of this exists as well as linkages of organisms to ancestors through DNA tracing. There is only need for the faithful ignorant to update their knowledge and understanding of evolutionary science so they can begin a factual debate.
Here is just one example of such evidence:
And some of the papers relating to this experiment:
This is by no means the only documented case of speciation.
As some have said, it is exceedingly difficult to reject evolution if you understand natural sciences (without a biased agenda) and the evidence it offers.
