Since the North American continent is very diverse when it comes to physical geography, one of the main factors would be river flows and mountain chains affecting transportation routes within the continent, and oceans and mountain chains affecting rainfall that is vital for the crops.
Answer: iron-making
Explanation: The varied climates and natural resources of Africa offered opportunities for developing different lifestyles. By 500 B. C., the Nok people of West Africa had pioneered iron-making technology.
Can you post the list of options and then I might be able to answer :)