题目类型：
问答题
题目内容
low, lower, a lower; that, which, what
The scientists began investigating the link between IQ and vegetarianism because people with higher intelligence have____ risk of heart disease,____ has long puzzled doctors.
The scientists began investigating the link between IQ and vegetarianism because people with higher intelligence have____ risk of heart disease,____ has long puzzled doctors.
正确答案
a lower; which