There a number of natural mysteries in the world that even make scientists .
A. exists; confusing
B. are existed; confused
C. exist; confused
D. exist; confusing
网友回答
A. exists; confusing
B. are existed; confused
(答案→)C. exist; confused
D. exist; confusing
解析：there be /exists,stands,lies“存在，有”。scientists 是“感到迷惑的”，所以答案C。