For a class of 30. Students simulate chromosome behavior during mitosis and meiosis. Kit has 3 separate exercises demonstrating mitosis, meiosis, and crossing-over and chromosome aberrations. Kit contains all necessary beads and other materials for completing the exercises, plus teacher's manual. Kit is reusable with the purchase of Replacement Student Guide (SG) Pads. Replacement beads and connectors (item# 171041 to item# 171049) can be purchased separately.