What was the shared role of internal heat in differentiation and outgassing?

Correct answer: It melted materials, enabling their movement and density-based separation, and helped gases escape

Internal heat partially melted and mobilised material in the early Earth. This allowed denser materials to sink towards the centre and lighter materials to rise, producing differentiation. The same heat drove volcanic activity, through which gases such as water vapour and carbon dioxide escaped from the interior; this is outgassing. Surface cooling occurred later, so option C does not describe the shared role. Exam tip: link differentiation with melting and density separation, and outgassing with volcanic release of gases.