Final answer:
In the context of aplastic anemia, if only one cell line is affected, it is typically the red blood cells (RBCs). Aplastic anemia is mainly associated with a deficiency in RBC stem cells, and while it generally affects all blood cells, a scenario affecting a single line would most likely refer to RBCs.
Step-by-step explanation:
If only one cell line is affected in aplastic anemia, it typically involves the red blood cells (RBCs). Aplastic anemia is characterized by deficient numbers of RBC stem cells in the bone marrow. While the disease can be inherited, it can also be acquired due to external factors such as radiation, medication, chemotherapy, or infection.
It's important to note that aplastic anemia typically affects the production of all types of blood cells, not just one. However, if the question presupposes a scenario where only one cell line is compromised, it would most likely refer to the red blood cells line, considering aplastic anemia's characteristic impact on RBC stem cells.
Furthermore, hematopoiesis, which is the formation of blood cells, takes place in the bone marrow. This process includes the production of erythrocytes from the myeloid cell line, which are crucial for transporting oxygen throughout the body.