9. how did world war i change the way in which wars are fought?

World War I changed the way wars were fought because of the widely known trench warfare. Because troops inside the trenches were much more protected than troops outside, it led to much more prolonged battles.

this is not a question its simply asking you to read and write a few sentences and   the question on the bottom its fairly easy, you can do this!

food chain i would say only because there is competition on getting food and survival