Across
1
Gas essential for breathing
4
Naturally occurring inorganic solid
6
Unit of power
7
Center of an atom or cell
12
Precious yellow metallic element
13
Substance with pH above 7
Down
2
Hottest planet in solar system
3
Preserved remains of ancient life
5
Form of thermal energy
8
Molten rock beneath Earth surface
9
Solid with repeating atomic pattern
10
Substance with pH below 7
11
Unit of energy