Many theories concerning the causes of juvenile delinquency crimes committed by young people focus either on the individual or on society as the major contributing influence. Theories 【21】______ on the individual suggest that children engage in criminal behavior 【22】______ they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior. through 【23】______ with others. Theories focusing on the role of society that children commit crimes in 【24】______ to their failure to rise above their socioeconomic status 【25】______ as a rejection of middle-class values. Most theories of juvenile delinquency have focused on children from disadvantaged families, 【26】______ the fact that children from wealthy homes also commit crimes. The latter may commit crimes 【27】______ lack of adequate parental control. All theories, however, are tentative and are 【28】______ to criticism. Changes in the social structure may indirectly 【29】______ juvenile crime rates. For example, changes in the economy that 【30】______ to fewer job opportunities for youth and rising unemployment 【31】______ make gainful employment increasingly difficult to obtain. The resulting discontent may in 【32】______ lead more youths into criminal behavior. Families have also 【33】______ changes these years. More families consist of one parent households or two working parents 【34】______ , children are likely to have less supervision at home 【35】______ was common in the traditional family 【36】______ . This lack of parental supervision is thought to be an influence on juvenile crime rates. Other 【37】______ causes of offensive acts include frustration or failure in school, the increased 【38】______ of drugs and alcohol, and the growing 【39】______ of child abuse and child neglect. All these conditions tend to increase the probability of a child committing a 'criminal act, 【40】______ a direct causal relationship has not yet been established. 【21】