Biogeochemical Cycles helps students reconstruct the nitrogen, sulfur, and phosphorus cycles step by step using hints, visual prompts, and critical thinking. This resource supports AP Biology Unit 8: Ecology. Activities for students: Reconstruct the nitrogen, sulfur, and phosphorus cycles step by step — using hints, visual prompts, and logical reasoning to complete each process. Biogeochemical Cycles works well for whole-class instruction, online sessions, small groups, or self-paced learning. S