Final answer:
Normocytic anemia being due to peripheral destruction (hemolysis) or underproduction is 1. true, with conditions like sickle-cell disease causing the former and chemotherapy causing the latter.
Step-by-step explanation:
The statement that normocytic anemia is either due to peripheral destruction (hemolysis) or underproduction is true. There are three major groups of causes for anemia: blood loss, faulty or decreased red blood cell (RBC) production, and excessive destruction of RBCs. When examining RBCs, a common parameter measured is the mean corpuscle volume (MCV), which helps categorize anemia based on the size of RBCs.
Normocytic anemia is characterized by RBCs that are of normal size, which is indicative of either RBC destruction or underproduction. Conditions like sickle-cell disease and lupus erythematosus are examples where hemolysis can occur, leading to normocytic anemia. Similarly, disorders such as aplastic anemia or the impact of chemotherapy can result in the underproduction of RBCs, also causing normocytic anemia.