Why may physical weathering appear stronger on a vegetation-free slope?

Correct answer: The surface remains directly exposed to heat and rain

Vegetation acts as a protective cover over the ground. Leaves and branches reduce the direct impact of raindrops, while roots hold soil and partly shield cracks in rocks. On a vegetation-free slope, the rock and soil surface are directly exposed to sunlight, heating, cooling, and rainfall. Repeated heating and cooling can cause expansion and contraction, and rainwater can enter cracks and weaken the material. These conditions can make physical breakdown more visible.

Choice C is correct because the surface remains directly exposed to heat and rain. Choice A is wrong because a bare slope can receive sunlight; choice B describes chemical dissolution and is too absolute; and choice D is wrong because gravity still acts on every slope. Vegetation does not stop all weathering, but its absence removes an important protective layer. The question asks why physical weathering may be stronger, not why erosion is always greater.