Answer:
The post-transcriptional modifications in the mRNA produced as a result of the transcription in eukaryotes provide many advantages to the mRNA. 
The two post-transcriptional modifications are the addition of 7-methylguanosine cap at 5' end of mRNA called capping whereas the addition of the poly(Adenyl) tail at 3' end called tailing. 
The advantages of capping are: 
1. Protection of nascent mRNA from the degradation. 
2. Recognition by transcription factors helps in translation. 
The advantages of tailing are: 
1. Protection of the mRNA from enzymatic degradation in the cytosol. 
2. Transcription termination 
3. Export of the mRNA from the nucleus