Final answer:
The greatest risk of developing hypothermia is under cold and wet conditions due to the rapid heat loss from the body.
Step-by-step explanation:
The condition under which a person is at the greatest risk of developing hypothermia is cold and wet conditions.
Hypothermia occurs when the body loses heat faster than it can produce, and cold and wet conditions can significantly increase heat loss. When a person is exposed to cold and wet conditions, their body temperature drops rapidly, putting them at a higher risk of hypothermia.
For example, if a person is caught in a rainstorm in cold weather without proper protection, their clothing may become soaked, reducing its insulation properties. This can lead to rapid heat loss from the body, increasing the risk of hypothermia.