Response to Intervention is generally defined as a three - tier model of support from a school that uses research - based academic and / or behavioral interventions to maximize student learning and achievement. (teachhub.com)
There are a number of drawbacks such as the lack of expandable memory and no options to buy higher tier models with more memory. (goodereader.com)
Neither do many other top - tier models from last year, but it's becoming an increasingly popular feature this year. (androidauthority.com)