Those are all vacuum lines in that area, shouldn't be any fuel lines.
On the radiator support you should have a silver sticker, about the size of a 3x5 card that should have the vacuu line routing diagram. The area just to the left of the idle valve, where the vacuum lines connect, those are thermo switches for routing the vacuum and should have a nipple or nipples (for connecting the vac line) coming off the top.
You may find that one, or more, of the lines has come loose and may have to replace it. You may also find that the other end of the line connects under the intake manifold. The lines under the intake can be replaced without pulling the intake if you have a long set of needlenose pliers.
Look for the diagram, if yours is gone or unreadable, I can look on my CD for the 500's diagram this evening.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.