Across
1
Substance with pH below 7
3
Tissue that contracts for movement
6
Biological catalyst
8
Unit of force
11
Ball of burning gas in space
12
Disturbance that transfers energy
Down
2
Mass per unit volume
4
The Red Planet
5
Icy body with a tail near the sun
7
Measure of matter in an object
9
Form of thermal energy
10
Element found in all living things