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D.Members of an alliance had to defend each other if one went to war.

D.

Explanation:

How did Alliance Systems cause WWI? Secret alliances were formed prior to the outbreak of the war. After the Assassination of Franz Ferdinand the Archduke of Austria-Hungary the alliance systems went into effect leading to many nations protecting one another (i.e. Russia protecting Serbia from Austria-Hungary). Alliances prevented larger, stronger states from waging war on the smaller, weaker states.

before there were tanks, machine guns, windmills, and solar panels, the first civilizations emerged that create the history of humanity which provided the larger context for western civilization. uses of weaponry and technology were used very differently in the ancient civilizations than they are today. relating back to the times of the ancient mesopotamian civilization, technology kept advancing throughout the ancient egyptian civilization into the ancient greek civilization, and then finally the ancient roman civilization. as techniques and strategies were past down from civilization to civilization, each shared its own similarities, as well as varied differences. one trait they had in common was to commit violence and economically overpower one another. technology has ultimately advanced due to the knowledge transferred from generation to generation. uses of sophisticated weaponry and devices have created more opportunity for warfare and improvement in the work place. ancient civilizations became more powerful due to the advancements of technology. technology did not only create the use of violence, but it also the economies grow and become stronger, because production of trading goods rose like never before. the rivers, such as the nile, tigris, and euphrates all flourished, as well as destructed civilizations. each civilization had different uses for these rivers, however, some benefited more than others. when analyzing ancient civilizations, there   are things you must understand

explanation: