Final answer:
Exons are the remaining pieces of pre-mRNA spliced back together during the process of splicing, resulting in a mature mRNA molecule ready for protein synthesis.
Step-by-step explanation:
The remaining pieces, known as exons, are then spliced back together to form the final mRNA. During this process known as splicing, introns—the non-coding regions of the pre-mRNA—are removed. The spliceosome, which is a complex of proteins and RNA molecules, conducts this precise process. Once splicing is completed, the result is a mature spliced mRNA molecule that can be translated into protein. The specificity of splicing ensures that the exons are joined together without altering the reading frame, which is crucial for the synthesis of functional proteins.