Across
1
Smallest unit of an element
3
Amplified beam of light
4
Biological catalyst
7
Tissue that contracts for movement
9
Magnetic metallic element
11
Absolute temperature scale unit
Down
2
Group of similar cells
5
Our home planet
6
Chemical element in table salt
8
Unit of heredity
10
Icy body with a tail near the sun
12
Mass per unit volume