Across
1
Ball of burning gas in space
3
Biological catalyst
6
Substance with pH below 7
7
Naturally occurring inorganic solid
8
Gas form of a liquid
10
The Red Planet
12
Nerve cell in the brain
Down
2
Group of similar cells
4
Tissue that contracts for movement
5
Fourth state of matter
9
Magnetic metallic element
10
Measure of matter in an object
11
Unit of heredity