What periods were part of the paleozoic era? a. mesozoic b. pennsylvanian c. cretaceous and d. precambrian googling the answer wont . trust me. i've tried it

The answer is Pennsylvanian. I worked on this before. The Pennsylvanian era is a subperiod of the Carboniferous Period. i really hope this helps :)

answer; i believe the correct answer is (a) nigeria is the largest african crude (oil) supplier; /// so revenue from petroleum;