Based on events in Native America when the Europeans came, the correct pairs are:
When the Europeans came, they brought new diseases that the Native Americans had no immunity for. This led to millions dying which only got worse thanks to the Europeans overworking Native Americans.
As the Native American population went into a decline, the Europeans needed a newer and more resilient source of labor and so imported millions of Africans as enslaved people.
Find out more on European colonization in the Americas at https://brainly.com/question/670495.