Across
1
Nerve cell in the brain
4
Smallest unit of an element
5
Molten rock beneath Earth surface
7
Basic unit of life
9
Unit of energy
10
Chemical element in table salt
Down
2
Amplified beam of light
3
Path of a planet around the sun
4
Substance with pH below 7
6
Tissue that contracts for movement
8
Glass that splits light into spectrum