2.
wide open areas used for grazing and crops
4.
small rivers that drain into a larger river
5.
the variety of species in an ecosystem
7.
a type of gas that traps heat energy, warming earth
8.
large geometric designs or animal shapes drawn on ground
10.
objects left behind by past cultures
12.
people who move from place to place
14.
Worlds largest waterfall
15.
Driest desert in South America
