Mental ret_rd_tion that is environmental in origin has a specific physical cause.

true or false

Answer: False

Explanation: Mental "retdtion" is a condition, usually irreversible, characterized by less than normal intellectual ability with learning disabilities and social adaptation, which is usually present from birth or manifest in the early years of childhood.

In most cases, the cause of mental retdtion is unknown, but various conditions during pregnancy may cause or contribute to a child's mental retdtion, such as the use of certain drugs, excessive alcohol consumption, radiotherapy, and malnutrition.

Difficulties associated with premature birth, traumatic brain injury or very low oxygen concentration during delivery can also cause mental retdtion.