In approximately of the cases of intellectual disabilities, there is an identifiable cause related to biological or environmental factors; the most common of these is .

One-third; fetal alcohol syndrome

Explanation:

Fetal alcohol syndrome (FAS) is a condition that occurs in baby when a mother drinks alcohol excessively during pregnancy. This can lead to a large range of problems, such as short height, low weight, small head size, poor coordination, low intelligence and abnormal appearance. This is the most common cause of intellectual disabilities with an identificable biological or environmental cause.

answer: what do you mean

explanation: