<prompt> Mental retardation is defined as IQ less than-85807570  <response>: Ans i.e., d i.e., 70 Classification of mental retardationo A child with IQ 70 is called as mentally retarded.Degree of MRIQMild51-70Moderate36-50Severe21-35Profound0-20o IQ level between 71-90 is designated as borderline intelligence. 