Across
1
Tissue that contracts for movement
2
Center of an atom or cell
4
Glass that splits light into spectrum
6
Unit of electric potential
7
Gas essential for breathing
8
Unit of power
Down
2
Unit of force
3
Group of similar cells
5
Icy body with a tail near the sun
9
Basic unit of life
10
Curved glass that refracts light
11
Solid with repeating atomic pattern