Final answer:
The Balfour Declaration was a communication by the British government expressing support for the creation of a Jewish state in Palestine. It marked a significant moment in the history of Zionism and led to ongoing tensions between the Jewish and Arab communities in Palestine.
Step-by-step explanation:
The Balfour Declaration was a communication by British Foreign Secretary Arthur Balfour during World War I that expressed his belief that the British government should support the creation of a Jewish state in Palestine. It was a significant document that marked the accomplishment of the goal that pro-Zionist groups had worked toward for years. The declaration caused tensions and conflicts between the Jewish and Arab communities in Palestine that continue to this day.