下图是果蝇体细胞模式图，请据图回答：
该图表示的是（）性的果蝇
参考答案：雌
马柯维茨的资产组合管理理论认为，只要两种资产收益率的相关系数不等于1，分散投资于两种资产就具有降低风险的作用。( )
There ____ no buses, we had to walk home after work yesterday. [ ]
A. was
B. were
C. being
D. had
