271. The discoveries made by Nobel Prize winning geneticist Barbars McClintock are considered to be among the major ______ of twentieth-century biological science.
A. deliberations
B. regulations
C. suggestions
D. accomplishment
E. defences

272. In the United States, social activists who strongly ______ a particular law can attempt to obtain a constitutional amendment to ______ it.
A. concur with, rescind
B. object to, repeal
C. disagree about, support
D. identify with, nullify
E. interact with, ignore

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