There are no definitive parameters, maybe there was before, if Pangaea is BS and we stayed isolated to our own paloeolithic tribes.
But we all likely came from the same source, and have intermingled through travel for hundreds of thousands of years after emergence as one group....
...the science at sorting out who is what / from where, is not definitive because the subject matter is not.
1 that's a pretty big maybe saying that
maybe there were definitive physical traits before
2 if everyone came from the same source then right there there's only one race.
The simple logic is that races are social constructs applied to similar groups of people. Now while many of those people may share similar physical traits those traits are not exclusive to said race or even definitive indicators of a person being that race. Seeing how there's so much diversion in each socially constructed racial group.
Logic dictates that if a paramater is not a definite way of classifying something it cannot be said that its a defining factor to that group.
Now physical traits can me used as an educated guess to help me determine a persons race. But that in no way is scientific way to classify something. Nor does it bring about accurate results.
If i used stats that back up black youths high percentage of committing violent crimes and then said that it was behaviorally genetic to their race because the stats back that up does that seem like a good way scientific way to classify a group does it?