By siltation, as part of the bed load
<span>The study of the physical features of the earth and its atmosphere, and of human activity as it affects and is affected by these, including the distribution of populations and resources and political and economic activities</span>
By rename do you mean turn into an improper fraction?
if so, it is because without turning it into an improper fraction, you cannot subtract 3/4 from 1/4 because you would get a negative answer and that would be incorrect
