It's a polysome!!...This question has been one of the most repeated questions in Neet....do remember this....

**Polysome:**

A polysome refers to a complex of ribosomes that are attached to a single strand of mRNA (messenger RNA). In other words, it is a cluster of ribosomes simultaneously translating the same mRNA molecule. The term "poly" in polysome indicates multiple or many, and "some" refers to ribosomes.

**Formation of Polysome:**

When mRNA is transcribed from DNA, it moves out of the nucleus into the cytoplasm, where it serves as a template for protein synthesis. In the cytoplasm, ribosomes can attach to the mRNA and initiate translation, which involves the assembly of amino acids into a polypeptide chain according to the codons on the mRNA sequence.

When multiple ribosomes attach to the same mRNA molecule at different sites, they form a polysome. The ribosomes on the polysome can simultaneously translate the mRNA into multiple polypeptide chains, increasing the efficiency of protein synthesis.

**Advantages of Polysomes:**

1. Enhanced Efficiency: Polysomes allow for the simultaneous translation of multiple copies of the same mRNA, leading to a higher rate of protein synthesis. This is particularly advantageous for genes that produce a large quantity of proteins.

2. Co-translational Modifications: Polysomes also facilitate the coordination of co-translational modifications. As the ribosomes move along the mRNA, they can encounter enzymes or factors that modify the nascent polypeptide chain, such as adding sugar groups or folding the protein into its functional form.

3. Conservation of Energy: By translating multiple copies of the same mRNA simultaneously, the cell conserves energy by avoiding the need for repeated initiation steps in protein synthesis.

**Conclusion:**

The correct answer to the question is option A, polysome. A polysome refers to a complex of ribosomes attached to a single strand of mRNA. These polysomes play a crucial role in enhancing the efficiency of protein synthesis by allowing multiple ribosomes to simultaneously translate the same mRNA molecule.