Final answer:
In the 19th century, imperialism was motivated by political, cultural, and economic factors. This included the desire for increased influence and control, the spread of civilization, and the need for raw materials and markets. Building up military forces was necessary to secure and maintain colonies, compete with other nations, and protect national interests.
Step-by-step explanation:
In the 19th century, imperialism was motivated by political, cultural, and economic factors. Politically, European powers sought to increase their influence and control over other territories. Culturally, western countries believed it was their duty to spread their civilization and values to other regions. Economically, industrialized nations needed access to raw materials and markets for their finished goods.
The expansion of military forces was a part of this imperialistic endeavor. A strong military allowed these powers to secure and maintain their colonies. It also served as a means to compete with other nations and protect their interests. For example, Great Britain built up its military to safeguard its hold on India and to limit Russian access to Afghanistan.