Across
1
Reddish electrical conductor
4
Force that attracts objects together
5
Naturally occurring inorganic solid
6
Unit of force
9
Infectious microscopic agent
11
Hottest planet in solar system
Down
2
Gas essential for breathing
3
Icy body with a tail near the sun
7
Disturbance that transfers energy
8
Fourth state of matter
10
Compound containing oxygen
12
Preserved remains of ancient life
13
Magnetic metallic element