freezing

I was driving with my dad earlier and he told me my gas tank didn't have enough fuel in it. It's got over a quarter, but he says that it should be kept above half when it's below freezing or else the fuel line will freeze. Normally, I fill up at a quarter, but now I'm curious. Does it need to...

2012 MZ3 skyactive sat for 2 days in sub freezing temps. started it up and moved it briefly to clear parking space and then moved it back. Next day (still below freezing) won't start. engine cranked and battery was not dead but engine would not start. Couple days later, temp comes back above...