Things are ________ on Mars ________ on Earth because of the different gravity.
A:much lighter;than that
B:much lighter;than those
C:not so light;as that
D:not so light;as those
如图所示,连入电路中的电阻R1、R2、R3允许通过的最大电流分别为I1、I2、I3,且I1>I2>I3,则此部分电路中允许通过的最大电流是( )