- Childhood refers to the early stage of human development before adulthood. It is a time of innocence and dependence on parents.
- Adolescence is the period of transition between childhood and adulthood, marked by biological and psychological changes during puberty.
- Human development involves both quantitative changes, like physical growth, and qualitative changes, like improved cognitive abilities. Quantitative changes refer to increases in physical size, while qualitative changes refer to improvements in skills and complexity of functions.