In which population are immersion burns most commonly observed?

Immersion burns are most commonly observed in individuals with impaired sensation or limited mobility. This group of people, which often includes those with physical disabilities, neurological conditions, or advanced age, may not be able to respond quickly to hot substances or may be unable to move away from sources of scalding liquids. As a result, when immersed in hot water or other heated substances, they can sustain more severe and extensive burns due to their inability to react appropriately.

Infants, while also susceptible to immersion burns, are not the primary population in this context since their burns are typically linked to caregiver negligence rather than their own inability to respond. Teenagers and physically active individuals are less likely to be involved in incidents leading to immersion burns due to generally higher mobility and awareness of their surroundings.

Thus, those with impaired sensation or limited mobility represent the key population most at risk for immersion burns, making this the correct answer.