Across
1
Ball of burning gas in space
2
Group of similar cells
3
Glass that splits light into spectrum
7
Particle of light
8
Solid with repeating atomic pattern
9
Unit of force
13
Infectious microscopic agent
Down
1
Chemical element in table salt
4
The Red Planet
5
Force that attracts objects together
6
Unit of heredity
8
Icy body with a tail near the sun
10
Form of thermal energy
11
Compound containing oxygen
12
Curved glass that refracts light