在畜禽育种过程中,通常要计算留种群均值与全群均值,留种群均值与全群均值之间的差值通常称之为()
A.选择差
B.选择强度
C.选择反应
D.选择进展
参考答案:A
It's helpful to put children in a situation _____ they can see themselves differently. [ ]
A. that
B. when
C. which
D. where
免疫荧光技术采用
A.采用化学发光剂作为酶反应底物B.用化学发光剂直接标记抗原或抗体C.抗体包被在磁颗粒表面D.发光底物是二价的三联吡啶钌E.以荧光物质标记抗体