题目选项分析

After long years of indifferent reception by the scientific community, Barbara McClintock's subtle work on the genetics of corn has now been acknowledged to be of major importance; her analyses show that movable elements control the action of genes and thus cause mutations.

After long years of indifferent reception by the scientific community, it has now been acknowledged that Barbara McCiintock's subtle work on the genetics of corn is major in importance; her analyses show that movable elements control the action of genes and thus cause mutations.