What is the function of the nucleolus?

The nucleolus is a specialized structure found within the nucleus of eukaryotic cells and is primarily responsible for the synthesis of ribosomes. Ribosomes are essential for protein synthesis, as they are the cellular machinery that translates mRNA into polypeptides. The nucleolus is involved in producing and processing ribosomal RNA (rRNA), which is a key component of ribosomes.

During the process of ribosome assembly, rRNA is combined with ribosomal proteins, which are imported into the nucleolus from the cytoplasm. This assembly of rRNA and proteins forms the subunits of ribosomes, which are then transported out of the nucleolus and into the cytoplasm, where they function in protein synthesis. Therefore, the function of the nucleolus is closely tied to the production of ribosomes, making the choice of ribosome synthesis the correct answer.