smelting/processing
Smelting
Zeppelins bro
Sergeants
Corn, peanuts, and cassava had the greatest impact on food production in Africa, corn, peanuts, and sweet potatoes to China, and corn and potatoes to Europe.
diplomatic relations with other countries
A type of communication which has greatest impact is written communication
Not true it was the greatest impact. It is just part of history. There are many things that have made a greater impact.
African Americans and Women
This question is sort of vague but I would guess the Environmental Revolution would have the greatest impact on the future quality of life for humans on Earth mainly because if future generations live the way we do no (exploiting resources at an unsustainable rate) then aspects such as Global Climate Change and air pollution will continue to rise.
Spain had the greatest impact on Latin America.
Probably the pulley amongst the simple machines is having the greatest impact on mankind.
Climate has the greatest impact on an ecosystem.