Need help proofreading and editing this body paragraph

this is the last body paragraph for my essay, we are supposed to write about solutions other than building empires.

The Ultra-nationalism of building an empire is not the right way to preserve and expand a nation’s culture or to provide a secure source of natural resources. A way in which a nation can acquire a secure source of natural resources is through trade. One country can trade a specific good other country needs, with a good that they need. This trading practice will benefit you far greater than having a war to acquire resources; it will allow a nation to establish a trade network which will provide you with most or all of the natural resources you require. A nation cultures and religion can be preserved and even expanded by introducing new populations into your nation. If one country permits immigrants to come to their country they can teach these immigrants their culture and religion which will then promote some of them to practice this culture and even convert to the nation’s religion. This concludes that there are more peaceful methods to achieve a nation’s goal than to build empires.

Get rid of all instances of "you" and any of its forms.

http://www.albany.edu/eas/104/topten.htm
See #7.

Clarify all instances of "they" and any of its forms.
http://grammar.ccc.commnet.edu/grammar/pronouns.htm

Clarify all instances of "it."
http://www.google.com/search?q=vague+pronoun+reference&ie=utf-8&oe=utf-8&aq=t&client=firefox-a&rlz=1R1GGGL_en___US357

Make sure all singular antecedents have singular pronouns or other referents.
http://grammar.ccc.commnet.edu/grammar/pronouns.htm

it is an argumentative essay

Writeacher's corrections have nothing to do with whether the essay is argumentative or not. She is correcting the grammar and proper essay form.

Here's the edited version of your paragraph:

The ultra-nationalism associated with building an empire is not a viable approach to preserving and expanding a nation's culture or securing natural resources. Instead, nations can seek a secure source of natural resources through trade. By trading specific goods with other countries, each nation can acquire what they need without resorting to war. This trading practice not only benefits the nations involved but also helps establish a robust trade network, ensuring a steady supply of necessary resources. Additionally, the preservation and expansion of a nation's culture and religion can occur through the introduction of new populations. By welcoming immigrants and sharing their culture and religion, a nation can promote cultural diversity and potentially inspire others to adopt its practices. In conclusion, it is evident that there are more peaceful alternatives to achieving a nation's goals than pursuing empire-building.