Across
1
Tissue that contracts for movement
3
Magnetic metallic element
6
Solid with repeating atomic pattern
7
Substance with pH above 7
8
Biological catalyst
Down
2
Preserved remains of ancient life
4
Gas essential for breathing
5
Icy body with a tail near the sun
6
Basic unit of life
9
Particle of light
10
Push or pull on an object
11
Mass per unit volume
12
Naturally occurring inorganic solid