In which of the following disease normal structure of hemoglobin but their RBC volume reduced in-

(Thalassemia) (535- Ganong 22nd) (76- 77- K.S 4th) (527- 23rd)Thalassemia - in which hemoglobin chains are normal but produced in decreased amounts or absent because of defects in the regulatory portion of globin genesChronic blood loss - due to continuous loss of blood lot of iron is lost from the body causing iron deficiency. This affects the synthesis of hemoglobin resulting in less hemoglobin content in the cells. The cells also become small. Hence the RBCs are microcytic and hypochromic