Across
1
Natural satellite of Earth
3
Icy body with a tail near the sun
4
Substance with pH above 7
6
Center of an atom or cell
9
Preserved remains of ancient life
11
Precious yellow metallic element
12
Compound containing oxygen
Down
2
Push or pull on an object
5
Naturally occurring inorganic solid
7
Path of a planet around the sun
8
Absolute temperature scale unit
10
Mass per unit volume
13
Element found in all living things