How did geography impact Sparta’s military tactics during the Peloponnesian War? Sparta did not have to worry about an invasion because it was located on top of a mountain.
Athens was located on an island, forcing the Spartans to use many ships to transport its army.
The stronghold of the Delian League was on Delos, requiring Sparta to have a strong navy.
Athens's location made it difficult to attack, forcing the Spartans to destroy farmland and crops.

Athens's location made it difficult to attack, forcing the Spartans to destroy farmland and crops.

Explanation:

Athens was  located high up on a hill. Having a high ground tend to be really beneficial in a war since it force the invaders to spent a lot of time and resources to reach their location.

On top of that, it made is easier for sides with higher ground to destroy the opposition with low range attacks. Meanwhile, the oppositions will have a hard time connecting their attacks.

Frustrated, Sparta decided to seek other methods to win the war. They destroyed farmland and crops In order to eliminate the soldiers' supply and weaken them.

i think its toxic gasses but i could be wrong