Across
1
Group of similar cells
2
Positive particle in nucleus
5
Mass per unit volume
6
Unit of energy
10
Natural satellite of Earth
12
Amplified beam of light
Down
2
Fourth state of matter
3
Our home planet
4
Absolute temperature scale unit
7
Magnetic metallic element
8
Compound containing oxygen
9
Path of a planet around the sun
11
Smallest unit of an element
13
Element found in all living things