Which of the following areas is the least radiosensitive?

Muscle tissues are considered the least radiosensitive area among the options provided because they have a lower proliferation rate compared to other tissues. Radiosensitivity refers to the susceptibility of cells, tissues, or organs to damage caused by ionizing radiation. Tissues that have high turnover rates or are rapidly dividing, such as bone marrow, skin, and linings of internal organs, tend to be more sensitive to radiation exposure.

Bone marrow, for instance, is highly radiosensitive due to its crucial role in generating blood cells, and because it contains rapidly dividing hematopoietic stem cells. Skin is also radiosensitive because it consists of layers of cells that reproduce frequently, particularly in the epidermis. The linings of internal organs, which also feature rapidly dividing cells for maintenance and repair, exhibit significant radiosensitivity.

Muscle tissues, in contrast, have a relatively stable and slow growth rate. While they can sustain some damage from radiation, they do not regenerate or reproduce as actively as the other tissues listed. Thus, in the context of radiation exposure, muscle tissues demonstrate the greatest resilience, making them the least radiosensitive option in this scenario.