Describe two factors that can contribute to resistance of weathering of rocks.

Explanation:

Although there are other factors involved, I have selected two most important factors that could play a vital role in the resistance of the rock weathering. Here I have discussed each of them briefly.

Rock composition: If a rock is compact and composed of minerals which are not easy to disintegrate by physical as well as chemical weathering, it will increase the resistance of natural rock weathering process. For example, if a rock is composed of high silica content, it will not easy weathered as compared to the rock which is composed of feldspar, calcite, and/or iron. Likewise, igneous rocks are more resistant to the sedimentary rocks because the minerals composition is more compact and dense.

Exposed surface area: If a rock is exposed to the natural environment, it could be weathered more quickly then the rock which is not exposed directly (e.g. underlying rocks). Therefore, covering a rock surface or reducing the surface area could contribute towards increasing resistance of rock weathering. This is the reason that deep underlying rocks stay intact for a longer period of time as compared the those which are exposed.  

the answer is na (sodium)