Across
1
Low-lying land surrounded by higher ground
3
Imaginary line around the middle of Earth
5
Flat grassland in tropical regions
7
Ridge of rock or coral near the surface
8
Wearing away of land by water or wind
9
Narrow sea inlet between cliffs
Down
2
Large natural elevation of earth
4
Distance north or south of equator
6
Line dividing two countries
10
Where river meets the sea
11
Region between the two tropic lines