Which principle of relative age dating is important for determining the relative age of igneous rock that has intruded into overlying rock?

The principle of cross-cutting relationships.

Explanation:

The principle of cross-cutting relationships states that an igneous intrusion is always younger than the rock it cuts across.

chinese civil war took place over a long period of time between 1927 and 1950. the war was interrupted when japan invaded china in 1936 and by world war ii. the war was fought between the nationalist government of china, also called the kuomintang (kmt), and the communist party of china (cpc).