Across
1
Precious yellow metallic element
3
Path of a planet around the sun
4
Fourth state of matter
5
Measure of matter in an object
6
Center of an atom or cell
9
Preserved remains of ancient life
Down
2
Amplified beam of light
3
Compound containing oxygen
4
Tectonic landmass section
7
Form of thermal energy
8
Ball of burning gas in space