Across
1
Absolute temperature scale unit
4
Center of an atom or cell
6
Preserved remains of ancient life
7
Ball of burning gas in space
8
Unit of energy
9
Reddish electrical conductor
12
Chemical element in table salt
13
Push or pull on an object
Down
2
Group of similar cells
3
Particle of light
4
Nerve cell in the brain
5
Tissue that contracts for movement
10
Gas form of a liquid
11
Solid with repeating atomic pattern