Because it causes them to move, and so they weather that way. Buut the acid rain can leak into the rock and slowly break down the atoms, causing it to chemically weather faster. Also, just regular water/rain can wash away some covering sediment.
I believe it is resources
The spindle fibers produced by the centrioles are necessary for the division of the chromosome at the time of the anaphase. In case, the centrioles do not perform their task, the genetic material in the cells may not divide equally due to the lack in the separation of the chromosomes. Hence, the problem with the centrioles may lead to the unequal division of the genetic material during the cell division process.
Hence, the correct answer is centrioles.