What is the most widely accepted theory on how early humans migrated to north america?

Suppose that sociologists and cultural anthropologists are tying to measure the amount of child abuse for cross cultural comparison. they run into disagreement over whether spanking a child is abuse or discipline. what problem are they encountering in their research? a. reliability of the definition of abuse. b. validity of the definition of abuse. c. occam's razor about the definition of abuse. d. none of these.