Answer the following conceptual questions about the factors affecting the acceleration due to gravity on celestial bodies.
(i) Two planets, A and B, have identical masses, but the radius of planet A is half that of planet B. Without using numerical values, explain which planet has the greater acceleration due to gravity and why.
(ii) If the mass of a planet is doubled while its radius remains unchanged, explain qualitatively how its surface gravity will change.
(iii) If the radius of a planet is doubled while its mass remains unchanged, explain qualitatively how its surface gravity will change.
Support each answer with the proportional reasoning involved.