Concept:This experiment demonstrates air pressure and surface tension. The paper stays stuck because outside air pressure pushes it against the glass, while surface tension of water seals the gap.Explanation:Students observed that the paper did not fall and water did not spill. Some thought glue was used, others thought water inside caused it. The teacher’s real aim was to spark scientific thinking. The activity helped students see that experiments are a key way to gain science knowledge. It pushed them to make observations and form their own explanations. It also made them curious and ask questions about the unexpected result. All three objectives were met: understanding experiments, explaining observations, and asking questions.Answer:D. (A), (B) and (C)