From piloting different curricula in the classroom, teacher training sessions, and adding additional Transitional Kindergarten (TK) classes, the Natomas Unified School District (NUSD) is building the foundation it needs to expand its transitional kindergarten classes for 4-year-old students by the 2025-2026 school year. TK is the bridge between preschool and kindergarten. Enrolling a child into TK is optional; however, research has shown that childrens’ brains rapidly develop more from birth to 5-years-old, according to First Things First; 90-percent of brain growth happens before kindergarten.