Across
1
Particle of light
4
Amplified beam of light
5
Absolute temperature scale unit
6
Naturally occurring inorganic solid
8
Our home planet
10
Ball of burning gas in space
Down
2
Group of similar cells
3
Curved glass that refracts light
7
Nerve cell in the brain
9
Tissue that contracts for movement
11
Unit of electric potential
12
Unit of power