Assess students' ability to analyze how four litter types—paper, plastic, food, and glass—affect a backyard pond's plants and animals. Scope: physical damage, water quality and oxygen changes, decomposition and nutrient effects, ingestion/entanglement risks, and food‑chain impacts; students should compare short‑ vs long‑term outcomes, design simple observational tests or safe classroom investigations appropriate for Pre‑K–Grade 2, and recommend age‑appropriate mitigation actions.