下列哪种生物技术能有效的打破物种的界限,定向地改造生物的遗传性状,培育新的农作物优良品种()
A.单倍体育种技术
B.诱变育种技术
C.杂交育种技术
D.细胞工程技术
参考答案:D
21. He apologized ________ late.
A.to his teacher to arrive
B.to his teacher for arriving
C.at his teacher to arrive
D.at his teacher for arriving
某产品具有4个功能领域F1、F2、F3、F4,其一对一强制评分后的修正得分、各功能的现实成本如下表所示。注:计算过程中保留三位小数。根据以上资料,回答下列问题:
F4的价值系数是()。
A.1.855
B.0.986
C.1.449
D.1.159