(a) Given what you have already learned in Chapter 2, discuss the likely heat budgets

(especially heat sources) within:

(i) A young Earth-like planet with a stabilized crust, fully formed core, and convicting mantle.

(ii) An ancient, rocky planet half the size of Earth with a large solid core, and greatly thickened lithosphere.

(iii) A young moon 3000 km in diameter, with a very small rocky core and a mantle and crust consisting predominantly of water-ice. This satellite is in a close elliptical orbit around a giant planet and displays recent evidence of widespread resurfacing.

(b) Which example (i, ii or iii) is least likely to exhibit volcanic activity, and which is most likely to exhibit volcanic activity? Give reasons for your answers.