— It's . Mine is ten yuan.
A:cheap
B:cheaper
C:expensive
D:more expensive
—No. It's difficult!
— Thank you for your coffee. I'm afraid I have to be off now.— OK, _______.
A和a、B和b是分别位于两对染色体上的等位基因,A对a、B对b为显性。基因型不同的两白花植株杂交,F1植株中紫花∶白花=1∶1。若将F1紫花植株自交,所得F2植株中紫花∶白花=9∶7。
请回答: