The Palestinian Territories are located on the borders of Israel, Jordan, and Egypt in the southern Levant (western Middle East). They are important in the Arab-Israeli Conflict since much of the conflict hinges on whether or not those territories will become the basis to an independent state of Palestine or not.
See the linked map for a clearer image.
The main reason is probably the fact that Israel still exists, and shows no sign of being willing to evaporate.
Zionism is certainly one of the causes of the Israeli-Palestinian Conflict. It is not the only cause of the conflict and is also not the most important cause of the conflict.
The dominant conflict in Palestine is between Israelis (who are predominantly Jewish) and Palestinians (who are predominantly Muslim), but the conflict is a political one, not a religious one.
The question as posed makes little sense.If I assume correctly, based on the word "Palestine's", that the conflict being referred to is the Israeli-Palestinian Conflict, please see a discussion of the causes of that conflict in this question: What are the causes of the Israeli-Palestinian Conflict?As for "the Palestine's" there is no such thing. If you wish to ask about the origin of the Palestinians, please see this question: What is the origin of the Palestinians? If you wish to ask about the origin of the term Palestine, please see this question: Where does the term Palestine come from?
Because your mom
It depends what you mean by "Palestine". If you are referring exclusively to the Palestinian Territories, there are abuses by Muslim Palestinians of Christian Palestinians and the defacing of their holy sites and monuments. Additionally, there is a conflict between Jewish Israeli Settlers and Israeli Soldiers and Palestinians (both Muslim and Christian). If you are using "Palestine" as a shorthand for "Israel and Palestine", then the religions in the conflict are Judaism, Christianity, and Islam. However, those religions are not at conflict. The Israeli-Palestinian Conflict is a ethnic/nationalist conflict where religions are used as ethnic identifiers (similar to the 1990s in Yugoslavia). It is not a theological conflict.
Both believe that Palestine is their holy land and that it belongs to them.
Syria
The major source of conflict is the existence of Israel.Others don't want it in the neighborhood at all.
Zionists started a movement to establish a Jewish state in Palestine.
Israel.
Arabs and Jews are in conflict over the territory of the former British Mandate of Palestine in the Middle East.