D) Contour plowing is used to reduce erosion and sediment pollution.
Explanation:
Contour plowing in farming helps to prevent pollution by reducing surface erosion of topsoil and preventing sediment pollution. 
Contour plowing is a farming technique in which crops are planted along the slopes of hills or contoured areas. 
- The rate at which rain water and precipitation moves along slope terrain is very fast. 
- This causes the washing off of the the topsoil on hills to eroded very fast. 
- Contour plowing breaks the slope and farming is done along movement on the contour. 
- This prevents topsoil erosion. 
- It also prevents sediment pollution in nearby streams and water bodies that are located around the valley at the base of the hill. 
Learn more: 
Soil erosion brainly.com/question/2473244
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Solution:
The troposphere is the atmospheric layer closest to the planet and contains the largest percentage (around 80%) of the mass of the total atmosphere. 
The troposphere is the lowest major atmospheric layer, extending from the Earth's surface up to the bottom of the stratosphere. The troposphere is where all of Earth's weather occurs. It contains approximately 80% of the total mass of the atmosphere.  
The troposphere is characterized by decreasing temperature with height (at an average rate of 3.5 degrees F per thousand feet, or 6.5 degrees C per kilometer). In contrast, the stratosphere has either constant or slowly increasing temperature with height.  
Thus the right answer is troposphere.
 
        
             
        
        
        
Founding population arrives, biogeographic isolation occurs, genetic changes