Test learners' ability to apply life-cycle thinking to compare environmental impacts of single-use plastic versus reusable coffee cups by defining system boundaries, identifying life-cycle stages (raw materials, manufacture, transport, use/cleaning, end-of-life), selecting relevant impact indicators (e.g., GWP, energy use, waste), estimating or interpreting break-even reuse numbers, evaluating behavioral and scenario sensitivities, and making evidence-based recommendations to reduce impacts.