Across
1
Gas essential for breathing
4
Disturbance that transfers energy
5
Amplified beam of light
8
Element found in all living things
9
Naturally occurring inorganic solid
10
Chemical element in table salt
Down
2
Basic unit of life
3
Biological catalyst
6
Unit of electric potential
7
Center of an atom or cell
11
Molten rock beneath Earth surface
12
Reddish electrical conductor
13
Nerve cell in the brain