1.
only provides the basic needs of a family
2.
growing crops to sell for a profit
3.
raising of animals for food
4.
boundary where higher area drops to lower land
5.
process of collecting water use in agriculture
6.
rich soil made up of sand and mud
7.
removal of salt from seawater
8.
seawater has been drained to create a new land
9.
cutting down trees and burning area
11.
materials or substance occur in nature
12.
that can be replenished in a short time
13.
resource that can't be replaced
14.
formed in the Earth by plant and animal remains
16.
electricity produced by natural steam
17.
energy created by splitting an atom
18.
act of protecting Earth's natural resources
19.
natural resources are available today and in the future
20.
electricity powered by water
21.
complex community of living things and physical environment
22.
forest in the far northern regions of the Earth
23.
loss of forest for logging and farming
24.
wide variety of life on Earth
25.
effort to restore forests
26.
area turns to a desert
27.
land flooded with water permanently or seasonally
28.
precipitation carrying large amounts of dissolved acid
29.
haze caused by chemical fumes
30.
layer layer that blocks out most of the harmful rays of the sun
31.
permanently frozen layer of soil
32.
plants and animals that ride along the water currents
