Final answer:
The armies of five Arab countries invaded Israel in 1948 because they saw the Zionists as invaders who had stolen Arab land. The invasion was a response to the United Nations' plan for a Jewish homeland in Palestine.
Step-by-step explanation:
The armies of five Arab countries invaded Israel in 1948 because the Arab countries saw the Zionists as invaders that stole Arab land. The Arab Palestinians and their neighbors did not recognize the new state of Israel and believed that they had a right to self-determination. The invasion was also a response to the United Nations' plan for a Jewish homeland in Palestine, which allocated more land to the Zionists than could be justified by their numbers at the time.