To solve this problem, we need to understand the causes of thalassemia and sickle cell anemia in terms of globin molecule synthesis.$\newline \bullet$Thalassemia:$\newline$ - Thalassemia is a genetic disorder characterized by the reduced synthesis of one or more of the globin chains that make up hemoglobin.$\newline$ - This results in an imbalance in the ratio of alpha to beta globin chains, leading to ineffective erythropoiesis and anemia.$\newline$ - Therefore, thalassemia is due to a quantitative defect in globin chain synthesis.$\newline \bullet$Sickle Cell Anemia:$\newline$ - Sickle cell anemia is caused by a mutation in the beta-globin gene, leading to the production of abnormal hemoglobin known as hemoglobin S (HbS).$\newline$ - This mutation results in a qualitative change in the hemoglobin molecule, causing red blood cells to assume a sickle shape under low oxygen conditions.$\newline$ - Therefore, sickle cell anemia is due to a qualitative defect in globin chain synthesis.$\newline$Now, let's evaluate the options:$\newline \bullet$Option 1: Both are due to a quantitative defect in globin chain synthesis.$\newline$ - This is incorrect because sickle cell anemia is due to a qualitative defect.$\newline \bullet$Option 2: Thalassemia is due to less synthesis of globin molecules.$\newline$ - This is correct as thalassemia involves reduced synthesis of globin chains.$\newline \bullet$Option 3: Sickle cell anemia is due to a quantitative problem of globin molecules.$\newline$ - This is incorrect because sickle cell anemia involves a qualitative defect.$\newline \bullet$Option 4: Both are due to qualitative defect in globin chain synthesis.$\newline$ - This is incorrect because thalassemia involves a quantitative defect.$\newline$Therefore, the correct statement is Option 2: Thalassemia is due to less synthesis of globin molecules.