Assess students' ability to predict and explain how adding or removing batteries, bulbs, switches, or wires will change whether bulbs light and how bright they are in simple series and parallel circuits. Provide short diagrams or written circuit descriptions; require a prediction and a brief explanation in terms of battery power and circuit continuity (complete vs open paths) and the effects of series versus parallel arrangements. Suitable for grades 3–5, medium difficulty, apply-level tasks.