What happened in china during the warring states period of the zhou dynasty between 476-221 b. c.e.?

The Warring States period was a period in which the regional warlords annexed smaller states around them and consolidated their mandate.

The Warring States period witnessed the proliferation of iron works in China, replacing bronze as the dominant metal used in the war machine. The walls built by the states to keep away the nomadic tribes of the north and the other states were the precursors of the Great Wall of China. Trade also reached great importance, and some merchants reached a considerable power in the politics of government. Military tactics also changed. Unlike the Spring and Autumn period, most of the armies in the Warring States period made a combined use of infantry and cavalry, and the cars gradually fell into disuse.

im pretty sure it has something to do with the end of ww1

impeachment is when a president is committing treason or doing shading acts while in presidendcy therfor he can be impeached   by congress