Across
1
Force that attracts objects together
2
Solid with repeating atomic pattern
4
Group of similar cells
5
Particle of light
6
Molten rock beneath Earth surface
9
Magnetic metallic element
Down
2
Icy body with a tail near the sun
3
Positive particle in nucleus
7
Gas form of a liquid
8
Gas essential for breathing
10
Unit of energy
11
Infectious microscopic agent