Across
1
Particle of light
3
Solid with repeating atomic pattern
5
Biological catalyst
6
Unit of force
7
Force that attracts objects together
10
Curved glass that refracts light
12
Infectious microscopic agent
Down
2
Group of similar cells
4
Absolute temperature scale unit
8
Positive particle in nucleus
9
Center of an atom or cell
11
Nerve cell in the brain