Answer:
Explanation:
DNA is first transcribed into pre-mRNA in the nucleus. This pre-mRNA is larger than mRNA, because pre-mRNA contains introns as well as exons. After transcription, RNA splicing occurs in which introns are removed and exons are joined together by which the size of RNA decreases. After that , at the 5' end of pre-mRNA, 5' capping occurs and at the 3' end of pre-mRNA, 3' polyadenylation occurs. This finally mature RNA is called mRNA.
