Dear Student,
Mercantilism is a phenomena that led to the creation of monopolistic trading companies(single powerful trading company), such as the East India Company and these companies used to made profit by excluding competition, sometimes by war so that they could buy cheap and sell dear.
Also it results into war because at times some countries uses wars as a way to take advantage of the global trade and to overcome another nation's trade in order to increase their own trade. And they think that war is inevitable whereas peacefull coexistence is impossible to benefit trade . For them war and trade are parallel to each other.
Regards.