Erosion is a problem for people as it keeps the environment in a certain way.

Directions: Read the following passage and answer the following question.

One thing, probably the most significant one, that influences the life cycle of a rock is the natural phenomenon called Erosion. In fact, most of the enchanting landscapes that we find around the world today are a boon of this natural phenomenon. But it is not a blessing always. It can cause major problems as people living in different geographical regions in large numbers, with passage of time, get used to the environment of the region being in a certain way.    Any change in the topography that influences the overall environment can pose new challenges.  However, people can do many things to increase the pace of this phenomenon or slow it down to a great extent.  A significant factor that can cause erosion is of course weathering.
 
Water currents cause lot of erosion. Some times water falls as acid rain. Then it is capable of dissolving rock structures that are sensitive to acids.  For example Marble & limestone undergo weathering when exposed to acid rain. Apart from this, when it rains very heavily, as it happens during monsoons, it can cause flooding.  During the monsoons rivers and streams flow in full swing and the rushing water can cause mud slides and even erode large river banks. The huge waves in seas and oceans, which you can watch standing on a beach, cause much erosion. The continuous action of waves on the rocks pond them and with time, cliffs will crumble. This is the reason why you will often find sand & little pebbles on beaches instead of huge pieces of rocks.  Rushing water, like what we usually find in rivers and streams, moves very fast and as it runs down mountains or strong waves on the shores of oceans, rolls large rocks along.  Strong and powerful waves on the shores of seas and oceans also roll rocks. These causes the sharp, rough and pointed edges of the rocks get knocked off and worn out in this process.  This is the reason why river rocks are so smooth & beach pebbles look as if somebody had polished them all his life.