Final answer:
Accidental drowning is the second leading cause of death in children aged 12 years and younger.
Step-by-step explanation:
According to the information provided, accidental drowning is the second leading cause of death in children aged 12 years and younger in the United States. Therefore, the type of boating accident that causes most deaths is drowning. It is important to note that drowning can occur in various situations, such as in swimming pools, lakes, or rivers.