The town of alpine glen lies at the base of a mountain and next to the alpine river. in recent months, the people of the town have noticed that the river has become much muddier, and that silt deposits have been building up along the river banks. which of the following changes to the environment is the most likely cause of the change to the alpine river? a. trees were cleared from a mountainside, causing an increase in soil erosion. b. cattle or other livestock were introduced to the mountain, causing an increase in soil erosion. c. a new dam began operating on the river, causing soil to be added to the water. d. a new power plant increased the river temperature, causing the erosive force of the water to increase.