In which of the following is endoplasmic reticulum absent?
Cells of pancreas, salivary glands
Erythrocytes of mammals and prokaryotes
Cells of brain
The correct option is B Erythrocytes of mammals and prokaryotes Haematopoiesis is the formation of new red blood cells. During this process, red blood cell loses nucleus, endoplasmic reticulum. It enables the red blood cell to contain more oxygen-carrying hemoglobin so that more oxygen to be transported. The endoplasmic reticulum is a double membrane-bound organelle which is absent in prokaryotes. Therefore, option B is correct.