the mixture of gases that surrounds the earth and that we breathe
air
a large hole in the side of a hill, cliff, or mountain, or one that is underground
cave
a high area of rock with a very steep side, often on a coast
cliff
the general weather conditions usually found in a particular place: c______
climate
a structure that is built over a river to allow people and vehicles to cross from one side to the other
bridge
one of the seven large land masses on the earth's surface and usually consisting of various countries: c________
continent
an area, often covered with sand or rocks, where there is very little rain and not many plants
desert
to cause to fill or become covered with water, especially in a way that causes problems
flood
an area of land that is higher than the surrounding land
hill
a piece of land completely surrounded by water
island
an extremely large, round mass of rock and metal, which moves in a circular path around the sun or another star
planet
damage caused to water, air, etc. by harmful substances or waste
pollution
water, especially from a river or stream, dropping from a higher to a lower point, sometimes from a great height
waterfall
the planet third in order of distance from the sun, between Venus and Mars; the world on which we live
Earth
a very large area of sea
ocean
