question: What 's the main reason for the decline of the number of Orange Monarch butterflies ? .
answer: The disappearance of their habitat and food
turker_answer: The disappearance of their habitat and food is the main reason for the decline in the number of Orange Monarch butterflies .
rule-based: The main reason for the decline of the number of Orange Monarch butterflies 's the disappearance of their habitat and food . .