Across
1
Tissue that contracts for movement
4
Basic unit of life
6
Nerve cell in the brain
8
Smallest unit of an element
10
Second lightest element
12
Biological catalyst
Down
1
Molten rock beneath Earth surface
2
Mass per unit volume
3
Form of thermal energy
5
Solid with repeating atomic pattern
7
Unit of force
9
Precious yellow metallic element
11
Reddish electrical conductor