The statement that provides the most accurate investigation of why Ethiopia and Egypt have run into conflict over resources management is:
Ethiopia's building of a dam on the Nile could impact Egypt's use of the Nile because they lie downriver.
This statement directly addresses the core issue of resource management conflict between the two countries, focusing on the implications of Ethiopia's actions on Egypt's access to and utilization of the Nile River, which is crucial for Egypt's water supply.