Across
1
Group of similar cells
3
Gas essential for breathing
5
Naturally occurring inorganic solid
8
Fourth state of matter
9
Infectious microscopic agent
Down
2
Unit of electric potential
3
Compound containing oxygen
4
Ball of burning gas in space
6
Curved glass that refracts light
7
Icy body with a tail near the sun
9
Gas form of a liquid
10
Our home planet
11
Smallest unit of an element