When anne treisman (1960) repeated the research of donald broadbent in an attempt to clarify his theory that attentional processes act as a filter through which certain stimuli pass, she was able to verify his findings and extended his theory in different ways. this demonstrates the incredible value of?

This demonstrates the incredible value of replication.
Scientific reports are given credibility and validity through the process of replication which accounts to verify and increase the argument of the existing theory or evidence. Vital for science is how important an evidence that exists is supported or negated by another similar finding which stems to form new possible areas for research.

The answer to that would be prussia which would later be germany