In industrialized countries is the stage of the lifespan from approximately the late teens to the mid- to late 20s, which is characterized by exploration, instability, and flexibility in social roles, vocational choices, and relationships.

Emerging adulthood/Early adulthood

Explanation:

Emerging adulthood or Early adulthood refers to the span of time between adolescence and adulthood.

This term refers to young adults who do not have children and do not have enough income to be fully independent.

It's been suggested that this period of life goes between 18-25 years of age, where these young adults explore their options in life (either vocational, professional or emotionally). This period is characterized  by instability and feeling "in-between"

Therefore, emerging adulthood (in industrialized countries) is the stage of the lifespan from approximately the late teens to the mid- to late 20s, which is characterized by exploration, instability, and flexibility in social roles, vocational choices, and relationships

answer; participant observation method;