However at　times　this　balance　in　nature　is＿＿ resulting　in　anumber　of　possibly　unforeseen　e

问题补充：

However，attimesthisbalanceinnatureis＿＿，resultinginanumberofpossiblyunforeseeneffects．

A. troubled

B. disturbed

C. confused

D. puzzled

答案：

A. troubled

(答案→)B. disturbed

C. confused

D. puzzled

解析：从句子的后半部分的resultineffects可知balanceinnature受到了破坏。Disturb符合句义。