Which event is an example of the alliance system?

a. one country attacks another because a promise i made to a third country

b. a country conquers many other countries to exploit their resources

c. a country loses control of many of its overseas colonies

d. one country engages in a military arm race with another country

An alliance is an agreement between countries to help each other in conflicts and defend each other.  A. One country attacks another because a promise made to a third country is an example of an alliance.  Two countries made a pact and agree to protect each other.  In this situation, it is likely that the first country made an agreement with the third country and is attacking another country on behalf of the third country.

Hope this helps!!

the noble might have thought that the system was far because they had lot of things and riches and the serf would have thought that the feudal system was un fair because of the way they were treated.

this forms a narrow, steep sided inlet (sometimes deeper than 1300 metres) connected to the sea. the terminal moraine pushed down the valley by the glacier is left underwater at the fjord’s entrance, causing the water at the neck of the fjord to be shallower than the main body of the fjord behind it.