Across
1
Measure of matter in an object
4
Tissue that contracts for movement
5
Icy body with a tail near the sun
7
Compound containing oxygen
8
Glass that splits light into spectrum
9
Mass per unit volume
13
Unit of energy
14
Natural satellite of Earth
Down
2
Ball of burning gas in space
3
Chemical element in table salt
6
Biological catalyst
10
Unit of electric potential
11
Gas essential for breathing
12
The Red Planet