Final answer:
Adolescence is the period of transition from childhood to adulthood marked by puberty and significant psychological and social development. It usually starts from around age 13 and lasts until the early twenties. This stage includes both biological maturation and gradual movement towards social independence.
Step-by-step explanation:
Adolescence
Adolescence is the period of transition between childhood and adulthood. This developmental stage is marked by significant physical, cognitive, and psychosocial changes. Adolescence typically begins with the onset of puberty, which includes sexual maturation and rapid growth, and it lasts until a person reaches early adulthood. Although puberty can start in the pre-adolescent stage, known as the 'tweens' around 11 to 12 years old, it continues throughout adolescence. This period also coincides with important mental and emotional growth, as adolescents begin to develop a more complex understanding of the world, cultivate their independence, and establish their social identities.
During adolescence, the individual takes on new roles and responsibilities that prepare them for adult life, with many cultures marking this transition with certain rites of passage or legal acknowledgments of maturity. However, the exact age range for adolescence can fluctuate, generally encompassing the years from 13 to the early twenties.
Biologically, childhood concludes at the onset of adolescence, after which a person approaches the various stages of adulthood. In contrast to legal definitions of an adult, which may set the threshold at 18 for certain rights and responsibilities, adolescence is more broadly related to the developmental and transitional phases that a person experiences.