A:However, careful
B:Whatever, careful
C:However, carefully
D:Whatever, carefully
已知点A的坐标为(2,3),O为坐标原点,连结OA,将线段OA绕点O按逆时针方向旋转90o得OA1,再将点A1作关于X轴对称得到A2,则A2的坐标为( )
同一生物体内,遗传物质不完全相同的细胞可能是( )