Nativists would most likely have been opposed to which of the following

The correct answer is: "inmigration"

Nativism refers to a political approach that supports native inhabitants over inmigrants and which seeks to impose restrictions on inmigration. Its supporters never call themselves nativists or racists, they prefer to define themselve as patriots instead. Many arguments are used to support the nativist viewpoint, for example, stating that there is unemployed people in the US because inmigrants come to steal their jobs, or that inmigrants generate more public spending that revenue, etc.

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.