• §504 - Rehabilitation Act of 1975 Obliges accommodations for individuals with disabilities_[1]
• Title II - Americans with Disabilities Act of 1990 Enforces reasonable modifications to services, programs, and activities and effective communication with all_[2]
• §508 - Rehabilitation Act Amendments of 1998 Requires digital access for all, regardless of disability_[3]
• Numerous Settlements and Resolutions Clarify that institutions should design their activities and format their materials in an inclusive way_[4]

The UDL framework helps us design our online courses for accessible learning_[5], removing potential barriers and replacing them with more efficient and effective options as technology progresses, which benefits all learners universally_[6].

• Tier 1 Instruction Comprised of research-based curriculum design and implementation of high-quality instructional practices for all learners
• Tier 2 Intervention Includes accommodations to Tier 1 instruction designed for learners with exceptional educational needs

The UDL framework strengthens Tier 1 instruction by creating a foundation that is grounded in current education, psychology, and neuroscience research_[7] and by building frequent assessment measures into the curriculum design_[8], which may lessen the overall need for extraordinary measures in accommodating learners with exceptional needs_[9].

• Multisensory Learning Modes Although very little research exists to prove learners best retain information presented in their learning styles_[10], a wealth of empirical evidence suggests presenting information in multisensory modes can support learning_[11]
• Factors Affecting Learning Encoding, spacing, interleaving, testing, transferring, forgetting, and thinking metacognitively are hallmark principles of effective long-term learning_[12]; course structure, instructor interaction, and discussions are vital influencers of e-learning_[13]

The UDL framework supports learning through multimodal input by encouraging various means of representing information, through interaction and multisensory output by asking for learners to express what they know in diverse ways, and through long-term learning principles by engaging learners in their learning process_[14].

• 21st Century Skills Classified by actions or quality indicators in content knowledge and 21st century themes; learning and innovation skills; information, media, and technology skills; life and career skills_[15]
• 21st Century Tools Categorized by their role in collaboration, communication, creativity, critical thinking, feedback, innovation, presentation, problem-solving, productivity, reflection, and social networking_[16]

The UDL framework creates learning environments that are conducive to the practice of 21st century skills by representing content in a variety of ways using 21st century tools, embracing a range of skills through expressive choice, and strengthening learners' ability to plan, execute, and monitor skill sets_[17].