That is my father, that is my mother, and that is me. We are in a happy .
A:class
B:family
与植物相比动物体特有的结构层次是( )
The woman came to see John yesterday is his aunt.
生物量是指某一时段单位面积土地上生活的生物体干物质总量。生物量的大小及变化受水热条件的影响。下图是我国祁连山南坡亚高山灌丛草甸种群结构相似的四个研究区5-9月地上生物量变化图,研究区是祁连山重要的夏季牧场。据此完成下列各题。
如图,Rt△ABC中,∠A=90°,AD⊥BC于点D,若BD:CD=3:2,则tanB=( )
执行如图所示的程序框图,若输入x=8,则输出y的值为( )