Across
1
Ball of burning gas in space
2
Fourth state of matter
4
Nerve cell in the brain
5
Infectious microscopic agent
6
Gas form of a liquid
7
Preserved remains of ancient life
Down
2
Glass that splits light into spectrum
3
Amplified beam of light
5
Hottest planet in solar system
8
Substance with pH below 7
9
Curved glass that refracts light
10
Our home planet
11
Substance with pH above 7