Here is my part of an oral presentation about Second world war!
Second world war was a global war. It is generally considered to have lasted from 1939 to 1945, although some conflicts in Asia that are commonly viewed as becoming part of the world war had begun earlier than 1939.
The start of the war is generally held to be 1 September 1939, beginning with the German invasion of Poland; Britain and France declared war on Germany two days later.
It involved the vast majority of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, with more than 100 million people, from more than 30 different countries. In a state of "total war", the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources. Marked by mass deaths of civilians, including the Holocaust and the first use of nuclear weapons in combat, it resulted in an estimated 50 million to 85 million fatalities. These made World War II the deadliest conflict in human history.