Question

How did geography influence life and government on the Greek peninsula

Answer 1

High mountains and access to water (the sea, not rivers) meant that navies were critical for war and trade.  This also meant that the different city states of Ancient Greece were physically separated from each other.  This allowed each culture to have similarities (like language and religion), but also significant differences like the Spartan vs. Athens systems.  This also led to a particular type of farming and a limited ability to fight in open plains.  Hence the Hoplite system with phalanxes became dominant.