Thalassemia is a hereditary disease that primarily affects the blood. The correct option is option 1. Thalassemia is a group of inherited blood disorders that affect the production of hemoglobin, a protein responsible for carrying oxygen in red blood cells. Individuals with thalassemia have an abnormal production of hemoglobin, which leads to a decrease in the number of healthy red blood cells and a reduced ability to carry oxygen. This can result in symptoms such as fatigue, weakness, shortness of breath, and pale skin. Thalassemia can range from mild to severe, depending on the type and number of gene mutations involved. It is important to note that while thalassemia affects the blood, it can also have secondary effects on other organs such as the spleen.