All of the above reasons are correct. MTSS (Multi-Tiered System of Supports) is distinctly different from RTI (Response to Intervention) and PBIS (Positive Behavioral Interventions and Supports) because it combines all of these elements. MTSS includes high-quality core instruction, a three-tiered model of supports and services, universal screening for all students, and a comprehensive approach that addresses both academics and behavior. This comprehensive nature makes MTSS a more holistic and inclusive framework for supporting all students.