Kid #1: "Because they got hit by a giant rock!"
Kid #2: "A volcano exploded!"
Kid #3: "An animal scared them all away."
....Kid #3: "They got too old."
Teacher: "How do ants know how to follow each other?"
Kid #1: "They leave a trail of crumbs to follow!"
Kid# 2: "They follow the footprints of the other ones!"