Across
1
Compound containing oxygen
4
The Red Planet
5
Precious yellow metallic element
6
Center of an atom or cell
7
Icy body with a tail near the sun
8
Element found in all living things
Down
2
Unit of force
3
Substance with pH below 7
4
Naturally occurring inorganic solid
5
Unit of heredity
9
Reddish electrical conductor