Many mexicans who lived on land that was part of the mexican cession
a. had to give up their land and relocate to mexico.
b. became us citizens and added to the area’s population.
c. were not allowed to own property in the united states.
d. fought the americans even though the war was over.

I believe the answer is: B. became US citizens and added to the area’s population.

the mexican cession refers to the region of united states that taken from Mexico after united states won the mexican-american war. After winning the war, the previously united states citizens were forced to became US citizens, added to area's population, and had to pay their taxes to the american government.

letter d is correct.