Across
1
Basic unit of life
2
Gas essential for breathing
4
Glass that splits light into spectrum
5
Absolute temperature scale unit
6
Preserved remains of ancient life
10
Fourth state of matter
11
Particle of light
Down
2
Compound containing oxygen
3
Curved glass that refracts light
6
Push or pull on an object
7
Naturally occurring inorganic solid
8
Mass per unit volume
9
Blocking of light by a celestial body
12
Tissue that contracts for movement
13
Gas form of a liquid