What were some of the underlying causes for the Great War that broke out in 1914?

Research paper to be written on the causes of The Great War (WW I). This is the thesis with room to improve (see teachers response)Thesis: The growing competition in 1914 between European nations over desired land to expand their empires led to an increased hostility which facilitated the outbreak known as the Great War.Professor’s response: Very good, although you could suggest that one “land grab” was more significant than others.I will upload further instructions with a sample paper, along with sources to use. Must be cited Chicago style, 17th edition