It can be inferred from the first paragraph that previously it was thought that behavioural traits were______.
A. determined by nature
B. determined by nurture
C. determined by nature or nurture
D. determined by a mixture of nature and nurture
债券的分类按其发行是否具有担保可分为()和();按债权人的权益可分为()和不固定利率债券;按发行方式不同可分为()和()。
患者出现夜盲、毕脱斑是由于缺乏下列哪种维生素?()
A维生素A
B维生素B2
C维生素C
D维生素D
外用中药可发挥局部作用,也可发挥全身的治疗作用。()