The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
The two immediate and two long-term causes of the Peloponnesian War were the trade differences between city-states, the increasing power and influence of Athens, Sparta was jealous of the level of influence that Athens had in the region and though that Sparta deserved that kind of power too, Athens was not considered to the necessities of other city-states, political differences between Sparta and Greece.
Why might it be said that all Greeks lost the Peloponnesian War?
Answer:
Because all the city-states suffered considerable losses; human and material losses. These consequences weakened Greece to the degree of facilitating the conquer of this land at the hands of King Philip II of Macedonia.