Fill in the Blanks Oceans and rivers1Online version Fill in the gaps with the appropriate words. by Gabriel Pérez Comendador 1 smaller Waves water sea mass down moving rivers mass big water Earth An ocean is a of salt which covers a area of the surface of The . A sea is a of salt which covers a area . The water is always because of : ( caused by the wind ) . Currents ( they are like ) . Tides ( movements up and of the level of the ) .