— Carol, I read a very interesting Internet post on a website last night.
— Well, what does it say?
A:An electronic message
B:A long piece of wood
C:a job in an organization
基因型为EeXBXb的个体,产生的配子名称和基因型种类是 ( )
(1)在“探究杠杆的平衡条件”实验中,用弹簧测力计沿BC方向拉杠杆,使杠杆平衡,如图1所示.请画出:①弹簧测力计对杠杆拉力F的示意图;②F的力臂.
(2)如图2所示,开关闭合.①请在图中标出通电螺线管的N、S极;②用箭头标出图中磁感线的方向.