Across
1
Naturally occurring inorganic solid
5
Curved glass that refracts light
6
Nerve cell in the brain
8
Force that attracts objects together
9
Compound containing oxygen
11
The Red Planet
Down
2
Amplified beam of light
3
Form of thermal energy
4
Group of similar cells
7
Chemical element in table salt
8
Unit of heredity
10
Unit of force