How does human development explain the juvenile's separate legal treatment?

A juvenile = a person below the age of majority in criminal matters — in Nepal's child-law (and the CRC's Article 1), a child is every human being below eighteen years unless majority is attained earlier under the applicable law; the Children's Act 2075 and the Criminal Code 2074's juvenile faces both work with the under-eighteen boundary (with the liability-ladder inside it — Unit 5). The law's separate naming matters: the juvenile is not a small adult but a developing person — the legal category itself encodes the doctrine of diminished culpability and greatermalleability (Unit 4's rationale).