Given the question: I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: The Earth Dies Screaming Movie plot: A steam train rushes through the countryside a dead engineer in the cabin. It finally reaches a bend in the tracks and because of excessive speed, crashes. A car, the driver slumped over the wheel crashes into a wall. Finally a plane, the pilot unresponsive, crashes into trees. Everywhere people are collapsing dead. At the train station, on a golf course, everywhere they are dead.A single vehicle appears, the driver Jeff Nolan (Willard Parker) is alive but uncertain whats happened. He stops in a village and picks up a shortwave radio before checking on a couple people lying in the street to confirm they are dead.Grabbing his gun he takes over a local hotel. He tests his shortwave radio then the TV at the bar, there are now signals he can detect except for some strange rhythmic static. Preoccupied with the radio, Nolan doesnt see, Quinn Taggart (Dennis Price) carrying a gun and his wife Peggy (Virginia Field) enter the hotel. They demand to know who he is and any identification he may have.Taggart relaxes when he discovers Nolan is American which he assumes means he is not an enemy or the cause of the disaster. Taggart explains the situation is the same all over the South everyone is dead. Nolan tests military aircraft, he was on a routine flight with a new experimental craft. When he went up, everything was normal, but when he returned, everyone was dead.Taggart goes to check the surroundings of the hotel, and Peggy confides they are not married. Taggart recommended she tell this story if they encountered anyone. She doesnt have any other details to add because she was in an oxygen tent at hospital and only left when she couldnt contact any staffTaggart returns and explains his theory that the current circumstances were no accident, but the start of a war. It is only a matter of time before who ever won the war comes in to take over the country and seek out and kill survivors like themselves. Later Nolan notices a wrecked car that is now empty. A voice calls him from across the town square and it is Edgar... My question: What kills off most of the earth's population?
The answer is:
Aliens