which of the following structure is considered as factory of ribosomes

The structure that is considered as the "factory of ribosomes" is the Nucleolus. Here are the steps explaining why:

1. The nucleolus is a round body located inside the nucleus of a eukaryotic cell.

2. It is not surrounded by a membrane but sits in the nucleus.

3. The primary function of the nucleolus is to make ribosomes.

4. Ribosomes are made from proteins and ribosomal RNAs (rRNAs).

5. The genes for rRNA are in the DNA in the nucleolus.

6. The nucleolus makes rRNA and combines it with proteins to form incomplete ribosomes.

7. Therefore, due to its role in producing ribosomes, the nucleolus is often referred to as a "factory of ribosomes".