How is Greece's economy different from Italy's economy?

Answer 1

You posted this question under "Ancient Greece" as well as 'Greece" in general, so it's unclear which comparison you are after. Briefly: Ancient Greece - as today's Greece - is mountain-covered with few arable areas. Greece's mountains also caused the development of separate city-States instead of a more unified State and economy. Its economy was a mix of rural and trade-based: especially the coastal cities mostly lived by trade and established colonies all across the Mediterranean.

Rome was much more expansionist and although its domestic economy was mostly rural, it early on started adding tax income and tribute from other regions to its national income.

Today, Italy is the much more industrialized economy. Greece's industry always remained small-scale. Its tourism income is a much more important source of revenue in relation to its total income than it is in Italy. In that sense you could call Greece's economy much more 'services-oriented'.