Though there is no single, thoroughly researched and widely practiced âmodelâ of the RTI process, it is generally defined as a three-tier (or three-step) model of school supports that uses research-based academic and/or behavioral interventions.The Three-Tier Model is described below.hough there is no single, thoroughly researched and widely practiced âmodelâ of the RTI process, it is generally defined as a three-tier (or three-step) model of school supports that uses research-based academic and/or behavioral interventions. The Three-Tier Model is described below.
Franklin Delano Roosevelt is the US President who served the greatest number of years in office. He was President from 1933 to 1945, which was 12 years. Currently, Preside â¦ nts are constitutionally limited to two consecutive terms, adding up to only 8 years.
The longest serving president was Franklin Delano Roosevelt who served 4 terms and a total of 12 years 1 month and 8 days as the president of the United States.n March 21, 1947 America passed the twenty-second amendment (Amendment XXII) to the United States Constitution and it was ratified by the requisite number of states on February 26, 1951 which limited the term any one person can serve as President.