Final answer:
Juvenility ends when an individual is biologically capable of reproduction, marking the beginning of adulthood. Legally, adulthood is commonly recognized at the age of 18, when individuals gain certain rights and responsibilities, with full legal adulthood in the U.S. typically achieved at 21.
Step-by-step explanation:
Juvenility ends when the body is capable of reproduction. You then become an adult. This transition does not have a precise age as it varies among individuals; biological maturity may occur around age 16 or 17. However, by law, a person is not considered an adult until they reach a certain age, which typically is 18 years old in many places, including the U.S. This is the age when individuals gain the right to vote and join the armed forces. Full legal and financial responsibilities often come at age 21 when one can also legally purchase and consume alcohol. Adulthood can be divided into three stages: early adulthood (20 to early 40s), where physical capabilities peak; middle adulthood, with its own unique challenges; and late adulthood. Each stage comes with distinct rewards and obstacles, with aging affecting individuals in various ways.