Final answer:
Infants and the elderly are the two age groups most at risk for suffering burn injuries, due to dependence on caregivers and physical vulnerabilities.
Step-by-step explanation:
The two age groups most at risk for suffering a burn injury are infants (children less than one-year-old) and the elderly. Infants have an incident rate of 20.6 per 1,000 infants, making them particularly vulnerable due to their complete dependence on caregivers for safety and protection. The elderly are also at high risk due to factors such as decreased mobility, thinner skin, and potentially slower reactions to dangerous situations.