All cheese including Cottage cheese is made from milk.
its the same thing. it doesn't change at all (it may taste worse)
it is made of curdled milk cottage cheese (aka curds and whey) is the first step in making any cheese, after that you separate out the curds, press them into a wheel, let the wheel age as desired.
cottage cheese is milk stirred until it is lumpy
Dry curd cottage cheese is made by adding either lactic acid-producing bacteria or acidifiers to skim milk and/or reconstituted nonfat dry milk