When a nation conquers and settles another country for its own benefit, this practice is called
assimilation.
the mission system.
the encomienda system.
colonization.

The correct answer is colonization. Colonization is when one country dominates (or colonizes) another, with the intent of using the colonized country's resources (such as land and labor) for the benefit of the colonizers. For example, Great Britain initially colonized what would become the US (the 13 colonies) and taxed the colonists for the motherland's gains. 

1and 3 i think sorry if wrong