Across
1
Unit of energy
3
Substance with pH below 7
6
Nerve cell in the brain
7
Preserved remains of ancient life
11
Hottest planet in solar system
Down
2
Disturbance that transfers energy
4
Natural satellite of Earth
5
Compound containing oxygen
8
Curved glass that refracts light
9
Center of an atom or cell
10
Absolute temperature scale unit