Across
1
Preserved remains of ancient life
4
Gas form of a liquid
6
Molten rock beneath Earth surface
8
Basic unit of life
11
Curved glass that refracts light
Down
2
Substance with pH below 7
3
Smallest unit of an element
5
Path of a planet around the sun
7
Fourth state of matter
9
Center of an atom or cell
10
Glass that splits light into spectrum