What are 3 earliest stages of human developent?

The three earliest stages of human development are the prenatal stage, infancy, and early childhood. The prenatal stage encompasses the time from conception to birth, where the foundation for physical and neurological development is established. Infancy, from birth to around two years old, involves rapid growth, sensory and motor development, and the formation of attachment bonds. Early childhood, from ages two to six, is characterized by further cognitive, emotional, and social development, including language acquisition and early learning experiences.