Where is rock breakage by thermal expansion and contraction more visible?

Correct answer: Dry regions with high day-night temperature range

Direct answer: Option A, dry regions with a large day-night temperature range. Thermal expansion and contraction are physical weathering processes. During the hot day, the outer part of a rock expands. During the cool night, it contracts. Repeated unequal expansion and contraction create stress, especially near the surface. Cracks may grow, and thin outer layers can eventually break away. Dry regions often have strong sunshine and a large daily temperature range, so option A is the best choice. Option B is less suitable because nearly constant temperature on the sea floor produces little repeated thermal stress. Option C is less suitable because permanent ice keeps temperature changes limited and hides the rock from direct daily heating. Option D is wrong because marshes with very little temperature difference do not provide strong repeated expansion and contraction. The process is physical, not chemical: the mineral composition need not change. Memory cue: hot day, cool night, repeated stress—think dry desert thermal weathering.