Across
1
The Red Planet
3
Smallest unit of an element
4
Molten rock beneath Earth surface
6
Curved glass that refracts light
7
Compound containing oxygen
10
Unit of energy
Down
1
Measure of matter in an object
2
Reddish electrical conductor
5
Biological catalyst
8
Force that attracts objects together
9
Element found in all living things
11
Natural satellite of Earth