The commodity most required for widespread violence is copper.
Copper is used to make brass, and brass is used for shell casings.
It's probably the most common element on battlefields since cartridge ammunition became widespread 150 years ago.
大规模暴力活动最需要的商品是铜。
铜用于制造黄铜，黄铜用于外壳。
它可能是150年前弹药广泛使用以来战场上最常见的元素。