Final answer:
Intellectual disability is the subject of this question.
Step-by-step explanation:
The subject you are referring to is intellectual disability. Intellectual disability is characterized by significant subaverage general intellectual functioning concurrent with deficits in adaptive behavior that manifest during the developmental period and adversely affect performance. It is diagnosed when a person earns a score approximately two standard deviations below the mean on an IQ test (about 70 on a test with a mean of 100) and has major deficits in adaptive functioning that were present before the age of 18. The Diagnostic and Statistical Manual of Psychological Disorders defines four subtypes of intellectual disability: mild, moderate, severe, and profound.