Final answer:
A fundamental issue of cross-cultural psychological research is the presence of cross-cultural variations. Different cultures have unique beliefs, values, and behaviors that can significantly impact psychological research findings.
Step-by-step explanation:
A fundamental issue of cross-cultural psychological research is the presence of cross-cultural variations. Different cultures have unique beliefs, values, and behaviors that can significantly impact psychological research findings. It is essential for researchers to acknowledge these cultural differences and avoid generalizing findings from one culture to another. For example, a study conducted in a Western culture may not be applicable to a non-Western culture due to differing cultural norms and practices.