Your exam wants YOU to read the data sheets on both processors and then answer the question.
The 5th question however, can not be easily gleaned from the data sheet unless they have figures for MTBF (Mean Time Before Failure). You could call or Email the Sales or Tech support staff of each manufacture to ask for this info.
This question is fairly wide open as there is quite a difference among the PIC16Fs and I think this also applies to the ATmegas but this is only in what peripherals are on the chips. This wouldn't apply the the exam question so don't get lost in those parts of the data sheets.
If there is anything specific in either data sheet you don't understand then post that question and a link to the data sheet in question with a reference to the page number.