下图是牛的整体骨骼示意图，图中编号G13所指属于下列哪一项？
A、跗骨
B、髌骨
C、胫骨
D、股骨
E、坐骨

单项选择题A． B． C． D．

多项选择题The matrix A has m rows and n columns. T(x)=Ax is a linear trasformation from to . Then which of the following statements is right. A、T is one-to-one if the kernel of T only contains the zero vector. B、T is onto if the range of T is . C、If T is one-to-one and onto, then m=n. D、The image of T is in .