List the primary features of autism? Which explanation for autism is no longer considered valid and lacks research support? What forms of treatment are helpful for a person with autism? List the criteria for a diagnosis of mental retardation. Explain one way in which sociocultural biases in testing might pose problems for assessing mental retardation. Of the four levels of mental retardation, into which category do most people with mental retardation fall? What are the main types of biological causes of mental retardation? What is the only way to prevent fetal alcohol syndrome? What are normalization and mainstreaming? What is your opinion about mainstreaming and normalization for children and adults with autism or mental retardation?