Across
1
Reddish electrical conductor
4
Second lightest element
5
Preserved remains of ancient life
6
Particle of light
9
Molten rock beneath Earth surface
10
Curved glass that refracts light
Down
2
Nerve cell in the brain
3
Infectious microscopic agent
7
Center of an atom or cell
8
Biological catalyst
9
Naturally occurring inorganic solid
11
Tectonic landmass section