Question

All efforts of cloning an animal will be ________ if there is not enough diversity in the group to overcome illness.

A．in need

B．in place

C．in vain

D．in case

Answer 1

C

词义辨析。A需要；B在合适的地方；C徒劳；D以防万一；结合句意可知C正确。句意：如果没有足够的多样性来克服疾病，所有克隆动物的努力都是徒劳的。