Consider the following statements in respect of cell and its structure: I. All cells possess cell wall. II. All cells have ribosomes present inside. III. All cells have well-organized nucleus. IV. All cells have linear DNA molecules present in them. Which of the statements given above is/are correct?

I is wrong: only plant cells, fungi and bacteria have cell walls; animal cells do not. II is correct: ribosomes (the protein-synthesis machinery) are universal to all cells, both prokaryotic and eukaryotic. III is wrong: prokaryotic cells (bacteria, archaea) lack a well-organised, membrane-bound nucleus. IV is wrong: prokaryotic DNA is circular, not linear; only eukaryotes have linear chromosomal DNA. Hence only statement II is correct.