Why was the ho chi minh trail important to the north vietnamese and the nlf?

Nwhich situations is the principle of cross-cutting relationships useful in determining relative age? check all that apply. a fault breaks through sedimentary layers. sedimentary layers form and then are tilted. igneous rock forms between sedimentary layers. sedimentary layers form over millions of years in a lake bottom. lava flows form on top of one another from several eruptions over time.