What changes when a mark is erased?

Correct answer: A mixture of graphite and clay

Ordinary graphite pencil cores use graphite and clay. Calling the core “lead” does not mean it is made of metallic lead.

Evidence: An ordinary pencil core is a mixture of graphite and clay, not metallic lead. The first section describes the pencil material.

Correct answer: It grips graphite on the paper and lifts it away.

Erasing physically removes graphite. It does not simply cover the colour or make the material disappear.

Evidence: A pencil eraser grips graphite left on paper and lifts it away. The key fact explains the removal process.

Correct answer: It penetrates the paper’s fibre network.

Ink’s penetration into paper fibres makes a difference. Special erasable-ink systems should not be judged by the same generalisation.

Evidence: Ordinary ink penetrates the paper’s fibre network, so it can be harder to erase than a pencil mark. The second section and table compare where the marks sit.