Across
1
Push or pull on an object
5
Amplified beam of light
6
Tissue that contracts for movement
9
Gas essential for breathing
12
Substance with pH below 7
Down
2
Ball of burning gas in space
3
Compound containing oxygen
4
Basic unit of life
7
Chemical element in table salt
8
Naturally occurring inorganic solid
10
Biological catalyst
11
Center of an atom or cell
13
Magnetic metallic element