Reduces carbon monoxide emissions from gasoline and improves fuel octane
        
             
        
        
        
Next time put the options down below but i've had this question before and the answer was First the sheet erosion, Then the rills, And lastly the gulliessheet 
 
        
                    
             
        
        
        
Uranium-235 is used. All of the isotopes of the element Uranium are radioactive, but Uranium-235 is the one commonly used. Some also use the radioactive isotope Plutonium-239.