In many cases, the formerly_ origins of disease have now been identified through modern scientific techniques.

Explanation

Correct Answer: B. mysterious Explanation: The sentence suggests that the origins of disease were previously mysterious and are now identified through modern scientific techniques. Why other options are not correct: - A. insightful: While scientific techniques can be insightful, the sentence implies that the origins were unknown. - C. cruel: Cruel is not fitting in the context of identifying the origins of disease. - D. notable: Notable is not fitting in the context of previously unknown origins. - E. useful: Useful is not fitting in the context of describing the origins of disease.