This document discusses physical development in children from birth through adolescence. It describes the stages of physical development as including infancy, childhood, adolescence, and adulthood. Key milestones of physical development are outlined for infants from birth to 2 years old, including sitting, crawling, and walking. The document also provides details on physical development expectations and activities recommended for children ages 2-6 years old. Factors that influence healthy physical development are hereditary, environment, balanced diet, daily routine, sleep, and receiving love.