Both of those fuel tanks are for the power unit. Rest assured of that. The reefer units will have a separate fuel tank for that unit, typically located under the chassis behind the cab.
Don't be fooled by the lack of a crossover between the two fuel tanks - the crossover system is obsolete, and no longer used. Both of those tanks feed the engine, still.
no
Yes. It is often refrigerated to make it more palatable.
If frozen, up to 12 months. If only refrigerated, then at most for two days.
Room temperature
No. Serve it at cool room temperature.
2 days
No - unless the label states "keep refrigerated" which should mean that it was in the refrigerated case when you purchased it.
After twenty four hours for sure.
No. It is ultra-pasteurized , but once opened, must be refrigerated.
It really should be refrigerated at all times because it could spoil,it should not be left out for more than 2 hours.
Yes. It really should have been refrigerated before opening, too.
Yes. Ricotta cheese is perishable and needs to be refrigerated. This makes sense because it needs to be refrigerated before it is used as an ingredient in foods so it still needs to be refrigerated. Cream cheese icings on cake should also be refrigerated.