图中a、b、c为海水等温线,且海水温度a>b>c,箭头代表洋流及其流向。下列四图中表示加利福尼亚寒流的图示是
A:A
B:B
C:C
D:D
下列不具有细胞结构的生物是( )
根据材料完成下列各题。BeethovenBorn in 1770 in GermanyA musician (音乐家)Died in 1827Florence NightingaleBorn in Italy on May 12th, 1820An English nurseDied in 1910Bill GatesBorn in I955 in the USAWrote Business @ the Speed of ThoughtOwns MicrosoftThomas EdisonBorn in 1847 in the USAMade over 1,000 inventions (发明)Died in 1931Yao MingBorn on September 12th, 1980 in Shanghai, ChinaA basketball playerPlayed for the Houston Rockets, the USA
一组数据经整理后分成四组,第一,二,三小组的频率分别为0.1,0.3,0.4,第一小组的频数是5,那么第四小组的频数是____.