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 shortest term in office was William Henry Harrison, who served for only a month. Only he and James Garfield served as President for less than a year. Andrew Johnson was the vice president who served the longest time as President without specifically being elected to the office.Lincoln was assassinated a mere month into his second term, so Johnson got to serve almost all of Lincoln's four-year mandate.he shortest term in office was William Henry Harrison, who served for only a month. Only he and James Garfield served as President for less than a year. Andrew Johnson was the vice president who served the longest time as President without specifically being elected to the office.