What countries have 3a's in its name?

Which is the best example of a primary source ducument useful in the study of history ?

What happened as agriculture became entrenched in the south ?

How did inca develop their road system? a) they used mortar to hold the stones together.b) they built suspension bridges over rivers. c) they mixed copper and stone together to make the blocks.d) they laid roads in the cities, not in the less densely populated deserts.