How would a government legally take control of another territory to add it to its own?
annex it.
append it.
incorporate it.
appropriate it.

The correct option is "Annex it. "

The annexation is a process, generally violent, by which one State or country seizes another, destroying, transferring or integrating all or part of its institutions, especially the Armed Forces that may have and their international political bodies (embassies, consulates , representations before international institutions). Although the annexations are not usually desired by the ruling class of the annexed country, they generally lose all or part of their power, if they can be desired by the majority of the population.

although world war i began in 1914, the united states did not join the war until 1917. the additional firepower, resources, and soldiers of the u.s. to tip the balance of the war in favor of the allies. remaining neutral. when war broke out in 1914, the united states had a policy of neutrality.