Ans. (4). protein synthesis.
Protein synthesis can be defined as a process that involves formation of polypeptides or proteins by using information present in DNA. It is divided into two steps, transcription and translation.
During transcription, DNA is transcribed into mRNA and information present in DNA is transferred to mRNA as codons. Codons represent triplet of nucleotides and each codon codes for a specific codon.
Translation involves formation of protein, during which amino acids are added to the growing polypeptide chain with the help of codons.
The given diagram represents process of translation. Thus, the correct answer is option (4).