Plz
why is it thought that the olmecs from central mexico came originally came from elsewhere?
a. because of facial characteristics found on large stone heads
b. because all cultures were settled by nomadic tribes
c. because the rubber used in their culture came from the philippines
d. because the jade-work they made has detail linking them to egypt

a--because of facial characteristics found on large stone heads

Explanation:

Even though the exact origin of the Olmec civilization still remains controversial, anthropologists point out to striking resemblance of the facial features found on huge monolithic heads to Africans.

Moreover, such theory is supported by the argument that some cultural traits found in Olmec civilization closely resemble characteristics of the Egypto-Nubian world of the same time period.

However, despite various theories speculating on the African, Chinese or even Nordic origins of the Olmec, there is no general scientific consensus regarding the issue due to the lack of sufficient evidence that would support such theories

answer; i believe the two groups were irish immigrants and chinese immigrants;

increase in population