The correct answer is: b. the removal of introns and alternative splicing of exons
Post-transcriptional regulation includes processes of regulation between transcription and translation such as RNA splicing, capping, addition of poly-A tail, RNA editing.
RNA splicing represents the process of RNA processing in which newly synthesized pre-mRNA transcript is converted into a mature mRNA. This process occurs only in eukaryotic organism and includes the removal of introns and joining together the exons. RNA splicing might occur during or immediately after transcription and it is performed by spliceosome (complex of small nuclear ribonucleo proteins).
Alternative splicing is a regulated process in which a single gene can code for multiple proteins because particular exons of a gene may be included within or excluded from the final mRNA.
To help the nervous system and brain develop.
DNA ligase is an enzyme that repairs irregularities or breaks in the backbone of double-stranded DNA molecules. It has important role in the process of DNA replication and DNA repair. It has three general functions: It seals repairs in the DNA, it seals recombination fragments, and it connects Okazaki fragments (small DNA fragments formed during the replication of double-stranded DNA). DNA ligase functions by forming a bond between the end of a “donor” nucleotide and the end of an “acceptor” nucleotide.