It will be 1 and 2.
This is not biology. This is Science.
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.
<span>The Cerebrum: The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe.</span>
It is called a cell membrane potential
