Final answer:
The largest number of 18-25-year-olds surveyed by Arnett likely indicated uncertainty regarding whether they have reached adulthood, reflecting a societal trend of delayed achievement of traditional adulthood milestones.
Step-by-step explanation:
In the Arnett survey, when 18-25-year-olds were asked if they feel like they have reached adulthood, the largest number did not provide a conclusive yes or no.
Instead, many are likely to express uncertainty or that they are in a transition phase, not fully identifying as adolescents but not entirely embracing all aspects of adulthood either.
This reflects a broader cultural trend where traditional milestones of adulthood, such as completing school, leaving home, becoming financially independent, marrying, and having a child are being attained later in life, often due to both cultural shifts and economic realities which effectively delay the onset of adult responsibilities and roles.