Across
1
Gas essential for breathing
4
Gas form of a liquid
5
Preserved remains of ancient life
6
Group of similar cells
7
Unit of electric potential
8
Disturbance that transfers energy
Down
2
Unit of force
3
Particle of light
9
Solid with repeating atomic pattern
10
Hottest planet in solar system
11
Unit of energy
12
Path of a planet around the sun