Across
1
Distance north or south of equator
3
Flat grassland in tropical regions
7
Half of the Earth
8
Cold treeless Arctic plain
9
Total number of people in an area
11
Region near the equator
Down
2
Deep narrow valley with steep sides
4
Mountain that can erupt with lava
5
Largest river in South America
6
Land surrounded by water
10
Where river meets the sea
12
Large slow-moving mass of ice
13
Narrow sea inlet between cliffs