题目:
While studying the genetic makeup of corn, a new class of mutant genes was discovered by Barbara McClintock, a discovery which led to greater understanding of cell differentiation.
选项:
A、a new class of mutant genes was discovered by Barbara McClintock, a discovery which led
B、a new class of mutant genes in corn were discovered by Barbara McClintock, leading
C、Barbara McClintock discovered a new class of mutant genes, and it led
D、Barbara McClintock discovered a new class of mutant genes, a discovery that led
E、Barbara McClintock, who discovered a new class of mutant genes, leading
答案:
D