Across
1
Ball of burning gas in space
2
Tectonic landmass section
3
Center of an atom or cell
7
Unit of force
10
Unit of heredity
Down
2
Particle of light
4
Curved glass that refracts light
5
Gas form of a liquid
6
Second lightest element
8
Unit of energy
9
Unit of power
11
Basic unit of life
12
Naturally occurring inorganic solid