Bi-amping a sub with a 2-channel receiver

[Jimbowne]

I have a sub with bi-terminals. I want to power it with a stereo receiver. The sub-woofer can handle 250Watts (rms). The stereo amp has 2 channels of 100watts a piece. I will have this stereo receiver hooked up to my main 5.1 receiver through its preout. My questions are:

a) What will happen if I only hook up one channel to the sub (right or left only)? Will it play only the lower frequencies from the right or left channel?

b) Can I bi-amp the sub with the right and left channels to produce 200 watts?

Any help/ suggestions are greatly appreciated.