Answer:
Athens's location made it difficult to attack, forcing the Spartans to destroy farmland and crops.
Step-by-step 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.