Don 't ask him to study too late into the night . _____ , he is only a small child.
A:As a result
B:Best of all
C:After all
D:For example
如图所示,在甲、乙两地之间沿直线架设两条输电线,由甲地向乙地输电,两条输电线总电阻为10Ω,甲地电源的电压为220V不变,下列说法正确的是
下列叙述中,属于生物共同特征的是( )