Across
1
Naturally occurring inorganic solid
4
Unit of electric potential
5
Icy body with a tail near the sun
6
Fourth state of matter
8
Magnetic metallic element
10
Group of similar cells
11
Nerve cell in the brain
Down
2
Path of a planet around the sun
3
Molten rock beneath Earth surface
5
Reddish electrical conductor
7
Measure of matter in an object
9
Mass per unit volume
12
Blocking of light by a celestial body