The series of changing of life of a human being is generally termed as human life cycle.
The state or period of babyhood and early childhood. The age of infants is generally upto 2 years.
Childhood is the time for children to be in school and at play to grow their mental capacity. The age in this stage is 3 to 8 years.
Adolescence is a transitional stage of physical and psychological development.The age of adolescence is 9 to 18 years.
The state or condition of being fully grown or mature. The age in this stage of life is 19 to 40 years.
It is simply the later part of normal life. The age of old age peoples is 41 years to death. This is the last stage of life.