Here's why:

* Granite's Composition: Granite is primarily composed of quartz and feldspar, both of which are highly resistant to chemical weathering.

* Limestone's Composition: Limestone is composed of calcium carbonate, which is easily dissolved by acidic rainwater.

The Process:

* Rainwater naturally absorbs carbon dioxide from the atmosphere, forming a weak carbonic acid.

* This acid readily dissolves limestone, leading to the formation of caves, sinkholes, and other karst features.

* Granite, being resistant to this chemical weathering, remains largely intact, although it may experience some physical weathering from processes like frost wedging.

Therefore, in wet climates, limestone weathers much faster than granite due to its susceptibility to chemical weathering by acidic rainwater.