Across
1
Low-lying land surrounded by higher ground
4
Seasonal heavy rainfall
5
Large area covered with trees
7
Half of the Earth
8
Chain or group of islands
Down
2
Largest ocean on Earth
3
Wearing away of land by water or wind
6
Imaginary line around the middle of Earth
9
Vast body of salt water
10
Region between the two tropic lines
11
Deep narrow valley with steep sides
12
Body of water surrounded by land