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.
Before the ratification of the 22nd Amendment, Franklin Delano Roosevelt was elected to four terms in the White House in 1932, 1936, 1940 and 1944. Roosevelt died less than a year into his fourth term, but he is the only president to have served more than two terms.