Across
1
Gas essential for breathing
4
Absolute temperature scale unit
5
Element found in all living things
6
Mass per unit volume
9
Unit of electric potential
11
Chemical element in table salt
13
Curved glass that refracts light
Down
1
Compound containing oxygen
2
Precious yellow metallic element
3
Tectonic landmass section
7
Path of a planet around the sun
8
Naturally occurring inorganic solid
10
Group of similar cells
12
Biological catalyst