Which of the following is probably least susceptible to microwave induced injury?

The liver is likely to be the least susceptible to microwave induced injury due to its unique physiology and regenerative capabilities. Microwaves primarily cause heating effects, which can lead to thermal injuries in tissues with higher fluid content and various structural vulnerabilities.

The liver, being a solid organ, has a robust blood supply and is capable of significant regional blood flow redistribution. It also has a high capacity for regeneration and repair, which allows it to recover from injuries more effectively than other organs.

In contrast, the eyes, urinary bladder, and gastrointestinal tract all contain epithelial tissues that are more sensitive to thermal damage from microwave exposure. The eyes, for instance, are very sensitive to heat and can sustain injury easily. The urinary bladder and gastrointestinal tract also have delicate mucosal layers that can be compromised by thermal injury. Therefore, the liver's inherent resistance to such damage makes it the least susceptible among the listed options.