Across
1
Amplified beam of light
4
Fourth state of matter
7
Element found in all living things
8
Particle of light
9
Reddish electrical conductor
Down
2
Naturally occurring inorganic solid
3
Substance with pH below 7
5
Gas form of a liquid
6
The Red Planet
7
Basic unit of life
10
Biological catalyst
11
Gas essential for breathing