CPM6372

I'm not exactly retarded, I was just currious to get some straight answers... Thanks to those who helped though!

Sorry if these are actually pretty stupid questions, I just love fooling around with my system and want to get a few things straight... 1. What does RCA stand for? (cables) 2. When connecting the RCA cables from an amp to a head unit, does it matter whether if they match up with positive/negatives on each unit? (they come in strands of two, does one have to connect to both positives and other both negatives?) 3. The wire that goes from your amp to your sub(s), what is it usually called? 4. Does this wire ^ have to match up with positive/negative too? 5. Why is the wire usually so thin if the wire powering the amp is so much larger like 0gauge or 4gauge? Hmmmmmm that's all I think of for now, thanks a lot!