power wire

is there a difference between power wire and ground wire?

To hook up two car batteries in parrlel would 4 guage wire cut it or should i go with 0 guage?

And if i go with 0 guage could i run it from the ositve and teh negative of the main battery into the truck, put them both into a distribution block, then run one 0 guage wire fromt hat for about 10 feet then put that through another distribution block adn have 2 come back out of it and hook them up to the second battery?