(1) Child development refers to the biological, psychological, and emotional changes that occur in human beings between birth and the end of adolescence, as the individual progresses from dependency to increasing autonomy. (2) It is a continuous process with a predictable sequence yet having a unique course for every child. (3) It does not progress at the same rate and each stage is affected by the preceding types of development. (4) Because these developmental changes may be strongly influenced by genetic factors and events during prenatal life, genetics and prenatal development are usually included as part of the study of child development. (5) Child care programs present a critical opportunity for the promotion of child development. (6) Developmental change may occur as a result of genetically-controlled processes known as maturation, or as a result of environmental factors and learning, but- most commonly involves an interaction between the two. (7) It may also occur as a result of human nature and our ability to learn from our environment.
Which sentence is irrelevant to the topic of the passage?