Why does the author include the example of harvesting submerged trees? To highlight new uses of technology
To point out how much timber is wasted
To emphasize the importance of sonar in forestry
To recommend the use of this technique in other aspects of the industry

just go with your heart buddy

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.