Which one of the following structures or components is not always present in living cells ?

Which one of the following structures is not present in a prokaryotic cell ?

Which one of the following is not found in animal cells ?

Eukaryotic cells are much more complex as compared to. prokaryotes. Which one of the following structures is exclusively present in a eukaryotic cell?

Which one of the following statement is not correct about cell wall?

Cell wall is absent in which one of the following organisms?