Completar frases ETAPAS DE LOS RIOSVersión en línea Completa las definiciones de las etapas de los rios por Alberto Pacetti Sánchez 1 river initial carried final slowy stage stage river initial final mountain slowy river rocks water flows flows river The source is the of the river . Upper course is the stage of the in the . Middle course is the where the more . Lower course is the stage and flows , it also deposit . The mouth is i the stage and the by the river into another .