Across
1
Particle of light
3
Second lightest element
5
Group of similar cells
6
Unit of heredity
7
Gas form of a liquid
11
Amplified beam of light
Down
1
Positive particle in nucleus
2
Nerve cell in the brain
4
Glass that splits light into spectrum
8
Center of an atom or cell
9
Path of a planet around the sun
10
The Red Planet