Across
1
Mass per unit volume
3
Molten rock beneath Earth surface
4
Gas essential for breathing
6
Gas form of a liquid
9
Reddish electrical conductor
10
Curved glass that refracts light
Down
2
Nerve cell in the brain
3
Tissue that contracts for movement
5
Push or pull on an object
7
Smallest unit of an element
8
Fourth state of matter