a) Where were most of the Greek settlements away from mainland Greece located b) why were such locations chosen

The most number of settlements of Greek people were in Anatolia. It was chosen because it was a strategic position.

Explanation:

a.

Anatolia was the most populous Greek region that was not a part of the mainland.

It is right across the Mediterranean sea, to the eastern side of the Greek mainland. It is the region which is known as Turkey.

b.

This land was suitable for settlement as it is in current from the Greek shore so it is easier to navigate from there.

These settlements eventually developed into huge trading cities as they stood on a strategic psoition in contact with Greece and the whole Mediterranean as well as the fertile crescent in Asia.