Complete the words in the text. Тема: Adventure. Natural features. Cliffs form where the land ends high above the water. In Arctic regions they are made of ice. 1) O have salt water in them and cover nearly 70% of the Earth. 2) S are also salty, but they are smaller. Usually they have land around most of their area.3) D are hills made of sand. The wind usually forms them behind sandy 4) b by the sea, or in 5) d like the Sahara. In some places, water from 6) r travels over rock. Over millions of years, it cuts the rock away.This can result in a large 7) v , such as the Hudson in the USA. Underground, moving water also creates 8) c like those in Jeita, Lebanon. A 9) v is a hill or 10) m which covers a gap in the surface of the Earth. Gas or lava can come out of this gap at any time.