Which cells are typically the most radio-sensitive?

The cells that are typically the most radio-sensitive are immature reproductive cells, as well as white and red blood cells. Immature cells, such as those found in the reproductive system, are more susceptible to the damaging effects of radiation due to their higher metabolic activity and rapid cell division. White blood cells are crucial for the immune response and also divide regularly, making them more vulnerable to radiation exposure. Red blood cells, while more stable than white blood cells, are still affected as they are produced from stem cells that are actively dividing.

This choice accurately identifies the class of cells that often exhibits the greatest sensitivity to radiation. Their rapid division and growth mean they have a higher likelihood of suffering irreparable damage when exposed to radiation, compared to more stable cells like muscle or nerve cells. Muscle and nerve cells tend to be more differentiated and have lower rates of cell division, which generally renders them less sensitive to radiation. Thus, the inclusion of immature, red, and white blood cells in the choice makes it the most appropriate answer regarding radio-sensitivity.