Across
1
Force that attracts objects together
4
Gas essential for breathing
7
Icy body with a tail near the sun
9
Infectious microscopic agent
10
Hottest planet in solar system
11
Molten rock beneath Earth surface
12
Push or pull on an object
Down
1
Precious yellow metallic element
2
Ball of burning gas in space
3
Solid with repeating atomic pattern
5
Biological catalyst
6
Unit of electric potential
8
Unit of force
9
Gas form of a liquid