Which of the following experiments demonstrates that both air and water are necessary for rusting?

The correct option is Iron in a container with water and exposed to air. This answer is correct because it matches the approved learning objective to describe experiments that show both air and water are necessary for rusting. (Chemistry only; WS 2.2, 7, 3.5) in the subtopic Corrosion and its prevention.

The correct option is Iron in a container with water and exposed to air. Iron in a container with water and exposed to air is correct because it directly supports the approved learning objective to describe experiments that show both air and water are necessary for rusting. (Chemistry only; WS 2.2, 7, 3.5). This belongs to the subtopic Corrosion and its prevention within Using materials, so the explanation must stay tied to that curriculum context. The other options are incorrect because they either do not answer this learning objective, use a vague statement, or move away from Corrosion and its prevention.