1.
The thin outer layer of Earth where we live
2.
The thick middle layer of Earth beneath the crust
3.
The layer of Earth made of liquid iron and nickel
4.
The innermost layer of Earth made of solid iron and nickel
6.
The layer of gases surrounding Earth
7.
All living things on Earth
8.
The solid, rocky part of Earth
9.
Rock formed from cooled magma or lava
10.
Rock formed from layers of sediment
11.
Rock changed by heat and pressure
12.
Melted rock beneath Earth’s surface
13.
Melted rock that reaches Earth’s surface
14.
The process that changes rocks from one type to another
15.
A resource that can be replaced naturally over time
16.
A resource that cannot be replaced quickly
17.
Coal, oil, or natural gas formed from ancient organisms
18.
Harmful substances added to the environment
