Across
1
Basic unit of life
3
Glass that splits light into spectrum
4
Our home planet
5
Nerve cell in the brain
8
Unit of energy
10
Mass per unit volume
11
Naturally occurring inorganic solid
Down
2
Gas essential for breathing
3
Fourth state of matter
6
Path of a planet around the sun
7
Substance with pH above 7
9
Compound containing oxygen
12
Unit of force