Where does the developmental life stage of emerging adulthood usually appear?

The developmental life stage of emerging adulthood usually appear usually during 18-25 but can be 18-29(Arnett,2000). It is the period of exploration or they want to try something new. Or in other words, Features of Emerging Adulthood is: First, the age of identity explorations. Second,the age of instability. Third,the self-focused age. Fourth,the age of feeling in-between; and lastly,the age of possibilities.

Sector is best defined as (part).