Mechanical weathering is the physical breakdown of rocks into smaller pieces without changing their chemical composition. In hot, wet regions, mechanical weathering is primarily driven by:

* Thermal expansion and contraction: The extreme temperature swings between day and night cause rocks to expand and contract. This repeated stress can eventually cause cracks to form and widen.

* Frost wedging: Water seeps into cracks in rocks, freezes, and expands, putting pressure on the rock. Repeated freezing and thawing can cause the rock to break apart.

* Root wedging: Plant roots can grow into cracks in rocks and exert pressure, causing the rock to break.

Basalt is a mafic igneous rock that is typically fine-grained and has a relatively high proportion of minerals that are susceptible to mechanical weathering, such as olivine and pyroxene. These minerals are prone to thermal expansion and contraction, making basalt more vulnerable to this type of weathering.

Granite is a felsic igneous rock that is typically coarse-grained and has a lower proportion of susceptible minerals. While granite can still experience mechanical weathering, it is generally more resistant than basalt.

Therefore, in a hot, wet region, basalt will weather more rapidly than granite due to its susceptibility to mechanical weathering processes.