[单项选择]20世纪以来生物科学最伟大的发现是（）。
A. 荷兰科学家雷文虎克发明了显微镜
B. 德国医学家魏尔啸创立了细胞生物学
C. 沃森和克里克提出了脱氧核糖核酸的结构模型
D. 美国内科学教授提出了医学模式的转变
E. 英国医学家哈维用实验方法首次阐明了血液循环理论

46) Scientists at Johns Hopkins have discovered "striking" differences between men and women in a part of the brain linked with ability to estimate time, judge speed, visualize things three-dimensionally and solve mathematical problems.
47)The differences, the researchers say, may underlie well-known trends that vary by sex, such as the fact that more men than women are architects, mathematicians and race-car drivers.
In a study reported this week in the Journal Cerebral Cortex, the researchers show that a brain region called the inferior parietal lobule is significantly larger overall in men than in women. The area is part of the cerebral cortex and appears on both sides of the brain just above ear-level.
Also, there’s a symmetry difference, with men having a larger left IPL than right. 48) In women in the study, it’s the right IPL that’s somewhat larger, though the difference between the two sides of the brain