The study,     in the online edition of the journal Brain, showed that after one year of musical training, children performed better in a memory test than     who did not take music classes.

A lot of ____ (family) have only a child in China.

二次函数y=ax²+bx+c（a≠0）的图象如图，则反比例函数 $y=-\frac{a}{x}$ 与一次函数y=bx﹣c在同一坐标系内的图象大致是（   ）

下列与ATP和酶有关的叙述不正确的是（  ）

下列有关染色体、 DNA和基因关系的叙述, 错误的是 (     )