Which of the following statements are correct?

(i) In prokaryotic cells, a special membranous structure formed by the extension of the plasma membrane into the cell is known as polysome.

(ii) The smooth endoplasmic reticulum is the major site for the synthesis of glycoproteins.
(iii) RuBisCO is the most abundant protein in the whole biosphere.
(iv) Mitochondria, chloroplasts and peroxisomes are not considered as part of the endomembrane system.