Across
1
Height above sea level
5
Line dividing two countries
6
Dry land with little rainfall
7
Largest river in South America
9
Flat grassland in tropical regions
10
Imaginary line around the middle of Earth
11
Cold treeless Arctic plain
12
Wearing away of land by water or wind
Down
1
Chain or group of islands
2
Piece of land jutting into the sea
3
Largest ocean on Earth
4
Total number of people in an area
8
Body of water surrounded by land
13
Largest hot desert in the world