question: Why can Bermudian blacks trace their ancestry back over centuries in Bermuda ?
answer: Bermuda 's black population was self-sustaining , with its growth resulting largely from natural expansion
turker_answer: Bermudian blacks can trace their ancestry back over centuries in Bermuda , because their population was self-sustaining , with its growth resulting largely from natural expansion .
rule-based: Bermudian blacks can trace their ancestry back over centuries in Bermuda because Bermuda 's black population was self-sustaining , with its growth resulting largely from natural expansion .