The process of formation of mRNA from the DNA strand is known as transcription. It is the first step in the process known as central dogma. This step is followed by a translation in which the proteins are translated from the mRNA containing the protein-encoding genes.
Among the given options, All options are correct except Option "3" which states Translational unit - Sequence of RNA with start codon only is incorrect as this unit in mRNA is flanked by the AUG codon which is the start codon produces a polypeptide chain and terminates at a stop codon.