Across
1
Molten rock beneath Earth surface
4
Group of similar cells
7
Blocking of light by a celestial body
10
Basic unit of life
11
Gas form of a liquid
Down
2
Disturbance that transfers energy
3
Icy body with a tail near the sun
5
Ball of burning gas in space
6
Glass that splits light into spectrum
8
Preserved remains of ancient life
9
Center of an atom or cell
12
Reddish electrical conductor
13
Unit of energy