Because for humanity it is a prerequisite of survival. 因为这是人类生存的前提
Over three-quarters of them by hand. 其中超过四分之三仅靠人力
The principal daily concern of all humans... 所有人类日常首要关心的
They learned to increase the yield and multiply the number of varieties. 他们学会了提高产量 种植多样化
They learned to adapt the grains that are the yeast of life... 他们学会了在不同的土壤和气候下
The memory of thousands of years scrabbling for food faded. 数千年来挣扎求食的记忆已经淡去