Hey guys, just a basic DIY guy here. Have a couple of questions about these two furnaces at my parents' place. The furnaces are gas furnaces, but can people identify what the lines are in the photos I've attached? I'm trying to figure out what each line is and what it carries. There are a total of 6 things I point to in the photos. I know this is very basic stuff, but I don't know much about HVAC stuff. Thanks a bunch for the help in advance.