下列函数中,在其定义域内既是奇函数,又是减函数的是( )
A:y=﹣x3
B:y=sinx
C:y=tanx
D:y=(12)x
(2015·四川)将苏云金杆菌Bt蛋白的基因导入棉花细胞中,可获得抗棉铃虫的转基因棉,其过程如下图所示(注:农杆菌中Ti质拉上只有T-DNA片段能转移到植物细胞中)。
大豆种子中贮藏营养物质的结构是( )
如图为温带草原生态系统示意图,请据图回答:
At the beginning of the 20th century, many people thought that the family was falling apart—__________, they thought it was dying. ( )