(a) Each local and regional board of education shall require each school under its jurisdiction to (1) offer all full day students a daily lunch period of not less than twenty minutes, and (2) include in the regular school day for each student enrolled in elementary school time devoted to physical exercise of not less than twenty minutes in total, except that a planning and placement team may develop a different schedule for a child requiring special education and related services in accordance with chapter 164 1 and the Individuals With Disabilities Education Act, 20 USC 1400 et seq., as amended from time to time. In the event of a conflict with this section and any provision of chapter 164, such other provision of chapter 164 shall be deemed controlling. Nothing in this subsection shall prevent a local or regional board of education from including an additional amount of time, beyond the twenty minutes required for physical exercise, devoted to undirected play during the regular school day for each student enrolled in elementary school.