Across
1
Ball of burning gas in space
3
Tectonic landmass section
4
Reddish electrical conductor
5
Measure of matter in an object
8
Absolute temperature scale unit
12
Naturally occurring inorganic solid
Down
2
Preserved remains of ancient life
3
Positive particle in nucleus
6
Unit of heredity
7
The Red Planet
9
Force that attracts objects together
10
Icy body with a tail near the sun
11
Nerve cell in the brain