Answers:
(1) Tupi, Arawak, Carib, and Nambicura.
(2) The slash and burn agriculture is a method of farming in forests that involves cutting down trees and burning away the under-bush to create fields for growing crops.
(3) The Portuguese colonized Brazil because they viewed Brazil as a trade post instead of a place to send larger numbers of settlers.
(4) The colonists enslaved Native people so they could be used into forced labor.
I hope this helped! ^^