Across
1
Compound containing oxygen
4
Amplified beam of light
5
Curved glass that refracts light
7
Particle of light
10
Biological catalyst
Down
2
Icy body with a tail near the sun
3
Unit of heredity
6
Mass per unit volume
8
Substance with pH below 7
9
Disturbance that transfers energy
11
Measure of matter in an object
12
Nerve cell in the brain