Across
1
Basic unit of life
4
Center of an atom or cell
6
Biological catalyst
9
Nerve cell in the brain
10
Precious yellow metallic element
Down
2
Amplified beam of light
3
Absolute temperature scale unit
5
Element found in all living things
7
Substance with pH above 7
8
Mass per unit volume
11
Group of similar cells
12
Our home planet