Autism is a severe developmental disorder, which if left unchecked, can usually progress to developmental disabilities at a young age. The causes of this disorder are largely unknown. It includes genetic and environmental factors. Symptoms may be present from, or even before birth, or appear gradually or suddenly after two or more years of apparently normal development. There is some evidence of alerted neurotransmitter levels; some children show slight physical changes, such as the shape …showed first 75 words of 3881 total…

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