Across
1
Fourth state of matter
5
Unit of electric potential
6
Reddish electrical conductor
7
Measure of matter in an object
9
Precious yellow metallic element
10
Compound containing oxygen
11
Blocking of light by a celestial body
13
Gas essential for breathing
Down
2
Group of similar cells
3
Preserved remains of ancient life
4
Gas form of a liquid
6
Icy body with a tail near the sun
8
Second lightest element
12
Natural satellite of Earth