"teh difference"? I loled... Does anybody remember that post I made recently, concerning a particular internet group?
Anyway, about your questions: All About Circuits isn't a free homework service. We prefer to help people who help themselves first, so please make an effort to solve your problem and post it. Afterwards we 'll try to help you in return.
About the second part of your question, however, I think it's clearly a specific bit of info, so I 'll just give it to you. The actual option is shift with carry and shift without carry:
When you shift a microprocessor's register to the left, you usually have two options. You can dump the bit that gets kicked out of it in the carry bit of the register or you can just ignore it and just remove it from the register.
In the same manner, if you shift right, you can import the register's bit in the leftmost bit of the register, or you can extend a '0' or a '1' in the MSB.