Across
1
Preserved remains of ancient life
4
Positive particle in nucleus
6
Absolute temperature scale unit
9
Mass per unit volume
10
Push or pull on an object
11
Measure of matter in an object
Down
2
Second lightest element
3
Gas essential for breathing
4
Tectonic landmass section
5
Ball of burning gas in space
7
Group of similar cells
8
Nerve cell in the brain