What are four items that historians used to find clues? ?

bits of pottery and clay, mounds containing the remains of cities, and ancient writing  

Documents, carbon dating, eye witnesses, fossils

the correct statement is letter a.   according to the mandate of heaven, kings were considered godlike beings, so they could do as they .

the mandate of heaven is a chinese political and religious ideology used since ancient times to justify the rule of the king or emperor of china, that has been in place since the zhou until the dynasty system ended. it has been created to justify the zhou as the main power of the region. in order to keep harmony, the ruler has to make what he wants and what people want. he had to make good choices to satisfy the people and then they will be happy and keep you in power.

on april 6, 1917, the u.s. joined its allies--britain, france, and russia--to fight in world war i. under the command of major general john j. pershing, more than 2 million u.s. soldiers fought on battlefields in france.