Across
1
Form of thermal energy
3
Element found in all living things
5
Preserved remains of ancient life
6
Biological catalyst
8
Blocking of light by a celestial body
9
Tectonic landmass section
10
Center of an atom or cell
11
Path of a planet around the sun
Down
1
Second lightest element
2
Compound containing oxygen
4
Group of similar cells
7
Naturally occurring inorganic solid