Across
1
Particle of light
3
Substance with pH above 7
4
Basic unit of life
6
Measure of matter in an object
7
Second lightest element
10
Amplified beam of light
11
Center of an atom or cell
Down
1
Fourth state of matter
2
Nerve cell in the brain
5
Unit of electric potential
8
Unit of heredity
9
Icy body with a tail near the sun
12
Unit of energy