Across
1
Mass per unit volume
5
Blocking of light by a celestial body
6
Absolute temperature scale unit
7
Center of an atom or cell
Down
2
Naturally occurring inorganic solid
3
Path of a planet around the sun
4
Biological catalyst
8
Compound containing oxygen
9
Amplified beam of light
10
Disturbance that transfers energy
11
Reddish electrical conductor
12
Measure of matter in an object