Answer:
Not 100% sure but I think its the Barail Range. This would affect them by the mountain acting almost like a barrier between them. So they didn't have much interaction.
The unsuitable factors for forming is '' salt,paints,poisnes substances,etc"
B is the answer to ur problem
Answer: A
Explanation:
roman empire founded - 27 bce
olmec founded - 1200 bce
egyptian empire collapse - 310 bce
maya collapse - 900 ad