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.