Final answer:
The Athenians took harsh actions against the people of Melos, launching a military expedition, capturing the island, and executing the adult men while enslaving the women and children.
Step-by-step explanation:
Once the people of Melos refused to surrender to the demands of the Athenians, the Athenians proceeded to take harsh actions against them. They launched a military expedition against Melos, besieging the island and eventually capturing it. The Athenians then executed all the adult men of Melos and enslaved the women and children.