Framing the question as why Israel occupies Palestine already sets the question as having a certain desired answer and also the lack of a definition for what constitutes "Palestine" makes the question difficult to answer.
"Palestine" is typically interpreted one of two ways. The first way is to refer to all of the land in the British Mandate of Palestine which includes the Modern State of Israel (except for the Golan Heights), the Gaza Strip, and the West Bank. The second way is to refer to exclusively those territories which the Palestinian Authority claims will serve as a basis for a future Palestinian State: the West Bank and Gaza Strip. Understandably, it changes the argument fundamentally if 78% of the territory in question is exempted from the discussion.
Additionally, the term "occupy" can be seen in either a neutral sense, i.e. that a group of people are in a certain piece of land, or in a negative sense, i.e. that a group of people are preventing a different group of people from exerting control over a piece of land. This answer will proceed under the understanding that "occupy" refers to the first, neutral definition.
As for the 78% of Mandatory Palestine which is now the State of Israel, this came about through Israel's acceptance of UN Resolution 181 and its border defense against Arab aggression to counter international laws that they did not like. As a result, the acquisition in the 1947-1949 of war was not an illegal act since self-defense is not a criminal act unless it is grossly disproportionate to the attack and the war was a relatively balanced affair as well as being resolved at the moment that each Arab state was willing to engage in an armistice. Just to clarify, this means that the 1949 borders of Israel belong to Israel.
As for the remaining Palestinian areas that were acquired in 1967, the situation becomes murkier, but as concerns the West Bank, Jordan attacked Israel first and Israel retaliated. Again the self-defense doctrine comes to the fore. Israel would have the rights to those territories acquired in self-defense. However, Israel was willing to concede some of those rights pursuant to a final, lasting peace with its neighbors, which is all that UN Resolution 242 discusses. Those states that have made peace with Israel since 1967 (Egypt and Jordan) have seen the return of territory (in Egypt's case) or the cession of the rights to occupied territory with tertiary partners (Jordan to the Palestinian Authority).
As for Gaza specifically, at this point in history, there are only two parties that claim it, the Palestinian Authority and Hamas. Since Hamas is not recognized as an independent government by any country, it retains exclusively de facto control of the area while the Palestinian Authority retains de jurecontrol pursuant to the Oslo Accords of 1993.
As for the West Bank specifically, since Israel ceded the possible claim to the West Bank to Jordan in UN Resolution 242 and Jordan then agreed to cede its rights to claim the land in full to the Palestinian Authority, the Palestinian Authority has the right to claim the lands of the West Bank. There are certainly Israelis who disagree with the extent of these rights, their viability vis à vis their religion, or use the doctrine of terra nullius to disavow the Palestinian Authority of these rights, but this is the minority of Israelis. Most Israelis want the majority of the West Bank to revert to the Palestinian Authority with a guarantee of peaceful coexistence.
To read more about Israeli-West Bank Issues, please read the Related Question below.
There are over 50 Islamic countries, so Palestine is certainly not the only Islamic country, but if you are considering Israel and Palestine, yes, Palestine is the Islamic country while Israel is the Jewish country.
The British Mandate of Palestine.
In 1944, Israel/Palestine was under British sovereignty as the British Mandate for Palestine.
The modern State of Israel was founded in the territory of the former British Mandate of Palestine in May 14, 1948.
No. No country is leased by or to another country. Additionally, Palestine had no ability to lease out territory given that it was not a country at the time of Israel's independence. Israel received independence as a result of the UN Partition Plan of Mandatory Palestine.
Israel is also known as the State of Israel or the Land of Israel. Palestine is also referred to as the State of Palestine or the Palestinian Territories.
Israel, in the area formerly known as Palestine until 1948.
no
To end violance between palestine and Israel.
The Ottoman Empire controlled Palestine and Israel in the 16th century.
No.
Palestinian Arabs fled Palestine after the establishment of Israel.
The Roman Empire referred to modern-day Israel as Palestine. Modern-day Israel was referred to as Palestine up until 1948. In 1948 the United Nations formed the country of Israel from the Palestine state.
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Palestine
It wasn't
There are over 50 Islamic countries, so Palestine is certainly not the only Islamic country, but if you are considering Israel and Palestine, yes, Palestine is the Islamic country while Israel is the Jewish country.