four early river valley civilizations
DESCRIPTION
Four Early River Valley Civilizations. Huang-He River. Indus River. Nile River. Tigris-Euphrates River. Environment poses 3 disadvantages :. 1. floods are unpredictable; sometimes no rain 2. land offers no barriers to invasion 3. land has few natural resources; building - PowerPoint PPT PresentationTRANSCRIPT