The answer to your question is A or true.
Answer:
Soil erosion causes siltation in rivers, dams, etc. In some areas, huge river deltas are formed (such as River Nile delta) because of soil erosion. Such places are good for agriculture but not good for urbanization. However, some people do not care about it, they just want to construct buildings on alluvium type soils.
Answer:

Explanation:
Waves affect the ocean by creating disturbances that move energy through the water.
As the wind blows on the surface of the ocean, waves are created that transmit energy through the water from a starting point to an end point.