question: On what point did Dobzhansky agree with Dr. Livingstone ?
answer: if races have to be ` discrete units , ' then there are no races
turker_answer: Dobzhansky agreed with Dr. Livingstone if races have to be `` discrete units , '' then there are no races .
rule-based: Dobzhansky agreed with Dr. Livingstone if races have to be ` discrete units , ' then there are no races .