Final answer:
The Greeks cared about Ionia because of its Greek population and cultural and historical significance. They were concerned about the fate of the Greek cities in Ionia under Persian rule.
Step-by-step explanation:
The Greeks cared about what happened to Ionia because it was a region on the western coast of Anatolia that was originally settled by Greeks and had a significant Greek population. Ionia was under Persian rule, and the Greeks considered it part of their cultural and historical heritage. The Greeks saw the Persians as foreign rulers and were concerned about the fate of the Greek cities in Ionia and the preservation of Greek customs and way of life.
Learn more about Greek concern about Ionia under Persian rule