Across
1
Group of similar cells
5
Mass per unit volume
6
Push or pull on an object
7
Biological catalyst
11
Positive particle in nucleus
12
Unit of electric potential
13
Magnetic metallic element
Down
2
Center of an atom or cell
3
Ball of burning gas in space
4
Absolute temperature scale unit
8
Smallest unit of an element
9
Unit of energy
10
Tectonic landmass section