Adult mainly refers to the mature and stable development of various organs of the human body, and the mature body and various physiological activities are relatively stable in the early adulthood. After the age of 30, the functions of various organs and systems of the human body gradually decline, and the incidence of physical diseases will also increase, such as respiratory diseases, cardiovascular and cerebrovascular diseases and so on. At the age of 50 -60, various functions of the body, such as physical strength, energy and immunity, all show a downward trend, and will become more obvious with age.
Psychological point of view: adults can live independently and assume family and social responsibilities, and generally have the most mature psychology in the middle of adulthood. Early adulthood and middle adulthood are the golden ages of life. During this period, memory, physical strength, learning ability and energy are more prominent, which is the best time to achieve your career through hard work. Because he is not naive, rich in social experience and cultural knowledge, he has become the backbone of all social undertakings, production and activities. He also knows the responsibilities and obligations, can form a family, can have children, and is the main undertaker of family pension.