Across
1
Molten rock beneath Earth surface
4
Biological catalyst
6
Amplified beam of light
7
Positive particle in nucleus
Down
2
Ball of burning gas in space
3
Substance with pH above 7
5
Natural satellite of Earth
7
Particle of light
8
Tissue that contracts for movement
9
Path of a planet around the sun
10
Basic unit of life
11
Mass per unit volume