Final answer:
Jordan acquired the West Bank and East Jerusalem as a result of the 1948 Arab-Israeli War.
Step-by-step explanation:
As a result of the 1948 war between Israel and the Arab countries, Jordan acquired the territory of the West Bank and East Jerusalem. During the conflict, also known as the 1948 Arab-Israeli War or the War of Independence, neighboring Arab states including Jordan, Syria, and Egypt entered into a conflict with the newly declared State of Israel. Subsequently, Jordan took control of the West Bank and East Jerusalem. These areas were initially part of a territory set aside for a future Arab state as per the United Nations partition plan which was rejected by the Arab countries.
The Palestinian territories of the Gaza Strip and West Bank would become central to the ongoing Israeli-Palestinian conflict, with the Gaza Strip being controlled by Egypt after the 1948 war and later by Israel after the 1967 Six-Day War until it was turned over to the Palestinian Authority.