Answer:
The event that led to the displacement of many Palestinians was the Arab rejection of the two-state solution in 1947.
Step-by-step explanation:
In 1947, the UN proposed the Two-State Solution as a way to divide the British Mandate of Palestine into two states, one Arab (where the Palestinians would live) and one Jewish (where the State of Israel would be established).
But the State of Israel did not accept this proposition, and took the territories attributed to the Palestinians as their own. In this way, the direct confrontations between Palestine and its representatives and Israel began, which generated a massive displacement of the Palestinian population towards other Arab countries.