The availability of a range of services and programs for students with special needs is commonly called

The continuum of services

Explanation:

The continuum of services could be described as service models designed to help provide specified instruction to students with disability. These services could be consultant teaching and intergrated co-teaching which are designed to help the student in his or her general classes. These makes learning easier for those category of student.

"social stratification refers to the way people are ranked and ordered in society. in western societies, stratification is primarily seen and understood as a result of socioeconomic status, which produces a hierarchy in which access to resources, and possession of them, increases from the lower to the upper strata"