article: There are many kinds of ants in America. One kind is very strong. People are afraid of it.
  These ants move in a large group. They eat all the animals on their way. They can kill and eat elephants, and they can eat wood houses. Sometimes even people are killed by them. When the ants come, people leave their homes. But people are sometimes glad after the ants pass through, because they can see no insects  or snakes.
question: Where are the insects or the snakes after the ants pass through?
options: They hide themselves under the ground. They have moved to other places before the ants come. They can be killed and eaten up by the ants. They were killed by people.