Which culture first developed an understanding of the concept of zero?

a) olmec
b) maya
c) aztec
d)mexica

How did the phillips brothers expand their businesses? by selling it to other businessmen by changing their source product by merging their companies by acquiring government support

When lincoln was first elected president, he hoped to prevent war by allowing (1) in the united states.

What is one way that the congress of vienna changed the map of europe?