某养鸡场拟培育产蛋量高的母鸡品种,你认为最佳的育种方法是( )
A:诱导基因突变
B:人工选择培育
C:杂交
D:诱导染色体变异
A:Our new school is big and nice. There is a gym in our school now.
B:Yes, and there is a big library, too.
如图,CD是△ABC的中线,点E是AF的中点,CF∥AB.