Which of the following types of cells is most radiosensitive?

Blood cells are indeed the most radiosensitive among the given options. This increased sensitivity is largely due to the characteristics of hematopoietic stem cells found in bone marrow, which are responsible for producing blood cells. These stem cells undergo rapid division and have a high rate of metabolic activity, making them more vulnerable to the damaging effects of ionizing radiation.

When exposed to radiation, the DNA within these actively dividing cells is more susceptible to damage, which can lead to consequences such as impaired blood cell production, reduced immunity, or an increased risk of leukemia. In contrast, nerve cells, muscles, and even bone cells tend to be more resistant to radiation, primarily because they are less metabolically active and do not undergo frequent division compared to blood cells. This distinction highlights the importance of cell division rates and metabolic activity when considering radiosensitivity in different cell types.