In the study of human development, a theory is a set of

Human development is a multidisciplinary scientific study of how people change and how they stay the same.
In the study of human development, a theory is a set of ideas that explains
development.
These theories describe the human growth, development and learning.

The median is 4 because 2 x’s out 9, 3 x’s out 7, 3 x’s out 5, and 4 is the only remaining number.

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